Sample leak stacks:

0:004> !heap -p -a 0x000000E48B59C890
    address 000000e48b59c890 found in
    _HEAP @ e483840000
              HEAP_ENTRY Size Prev Flags            UserPtr UserSize - state
        000000e48b59c830 0008 0000  [00]   000000e48b59c860    0004c - (busy)
        7ffd20358b04 ntdll!RtlpCallInterceptRoutine+0x0000000000000040
        7ffd20329f36 ntdll!RtlAllocateHeap+0x0000000000079836
        7ffd023eb4cd MSVCR120D!_heap_alloc_base+0x000000000000005d
        7ffd02400b1b MSVCR120D!_heap_alloc_dbg_impl+0x000000000000027b
        7ffd024010b9 MSVCR120D!_nh_malloc_dbg_impl+0x0000000000000039
        7ffd023fffd0 MSVCR120D!_calloc_dbg_impl+0x0000000000000080
        7ffd023fff1b MSVCR120D!_calloc_dbg+0x000000000000004b
        7ffd02416f2e MSVCR120D!calloc+0x000000000000002e
        7ffcf4606015 rubyprov!objspace_xcalloc+0x0000000000000055
        7ffcf45f2d24 rubyprov!ruby_xcalloc+0x0000000000000024
        7ffcf469607b rubyprov!iseq_alloc+0x000000000000004b
        7ffcf4692f9d rubyprov!rb_iseq_new_with_opt+0x000000000000001d
        7ffcf469330a rubyprov!rb_iseq_compile_with_option+0x000000000000023a
        7ffcf4583d9b rubyprov!eval_string_with_cref+0x000000000000037b
        7ffcf45844b1 rubyprov!eval_string+0x0000000000000041
        7ffcf4584531 rubyprov!ruby_eval_string_from_file+0x0000000000000071
        7ffcf4564caa rubyprov!rb_eval_string+0x000000000000001a
        7ffcf4522ee8 rubyprov!runStringGuarded+0x0000000000000028
        7ffcf458ea11 rubyprov!rb_rescue2+0x00000000000000e1

0:004> !heap -p -a 0x000000E48B59D390
    address 000000e48b59d390 found in
    _HEAP @ e483840000
              HEAP_ENTRY Size Prev Flags            UserPtr UserSize - state
        000000e48b59d330 0008 0000  [00]   000000e48b59d360    00054 - (busy)
        7ffd20358b04 ntdll!RtlpCallInterceptRoutine+0x0000000000000040
        7ffd20329f36 ntdll!RtlAllocateHeap+0x0000000000079836
        7ffd023eb4cd MSVCR120D!_heap_alloc_base+0x000000000000005d
        7ffd02400b1b MSVCR120D!_heap_alloc_dbg_impl+0x000000000000027b
        7ffd024010b9 MSVCR120D!_nh_malloc_dbg_impl+0x0000000000000039
        7ffd02401049 MSVCR120D!_nh_malloc_dbg+0x0000000000000049
        7ffd02401e9a MSVCR120D!malloc+0x000000000000002a
        7ffcf4605d57 rubyprov!objspace_xmalloc+0x0000000000000037
        7ffcf45f2cec rubyprov!ruby_xmalloc2+0x000000000000002c
        7ffcf4683fc8 rubyprov!iseq_set_sequence+0x0000000000000228
        7ffcf4682eac rubyprov!iseq_setup+0x000000000000011c
        7ffcf4674fac rubyprov!rb_iseq_compile_node+0x0000000000000ebc
        7ffcf4693016 rubyprov!rb_iseq_new_with_opt+0x0000000000000096
        7ffcf469330a rubyprov!rb_iseq_compile_with_option+0x000000000000023a
        7ffcf4583d9b rubyprov!eval_string_with_cref+0x000000000000037b
        7ffcf45844b1 rubyprov!eval_string+0x0000000000000041
        7ffcf4584531 rubyprov!ruby_eval_string_from_file+0x0000000000000071
        7ffcf4564caa rubyprov!rb_eval_string+0x000000000000001a
        7ffcf4522ee8 rubyprov!runStringGuarded+0x0000000000000028
        7ffcf458ea11 rubyprov!rb_rescue2+0x00000000000000e1

0:004> !heap -p -a 0x000000E4839192E0
    address 000000e4839192e0 found in
    _HEAP @ e483840000
              HEAP_ENTRY Size Prev Flags            UserPtr UserSize - state
        000000e483919280 000e 0000  [00]   000000e4839192b0    000b4 - (busy)
        7ffd20358b04 ntdll!RtlpCallInterceptRoutine+0x0000000000000040
        7ffd20329f36 ntdll!RtlAllocateHeap+0x0000000000079836
        7ffd023eb4cd MSVCR120D!_heap_alloc_base+0x000000000000005d
        7ffd02400b1b MSVCR120D!_heap_alloc_dbg_impl+0x000000000000027b
        7ffd024010b9 MSVCR120D!_nh_malloc_dbg_impl+0x0000000000000039
        7ffd02401049 MSVCR120D!_nh_malloc_dbg+0x0000000000000049
        7ffd02401e9a MSVCR120D!malloc+0x000000000000002a
        7ffcf4605d57 rubyprov!objspace_xmalloc+0x0000000000000037
        7ffcf45f2caa rubyprov!ruby_xmalloc+0x000000000000001a
        7ffcf464278a rubyprov!enc_register_at+0x00000000000000ba
        7ffcf4641dbd rubyprov!rb_enc_init+0x000000000000007d
        7ffcf4641753 rubyprov!rb_utf8_encoding+0x0000000000000013
        7ffcf46680d3 rubyprov!rb_w32_sysinit+0x0000000000000043
        7ffcf45acd5d rubyprov!ruby_sysinit+0x000000000000001d

0:004> !heap -p -a 0x000000E48390AD60
    address 000000e48390ad60 found in
    _HEAP @ e483840000
              HEAP_ENTRY Size Prev Flags            UserPtr UserSize - state
        000000e48390ad00 001e 0000  [00]   000000e48390ad30    001b4 - (busy)
        7ffd20358b04 ntdll!RtlpCallInterceptRoutine+0x0000000000000040
        7ffd20329f36 ntdll!RtlAllocateHeap+0x0000000000079836
        7ffd023eb4cd MSVCR120D!_heap_alloc_base+0x000000000000005d
        7ffd02400b1b MSVCR120D!_heap_alloc_dbg_impl+0x000000000000027b
        7ffd024010b9 MSVCR120D!_nh_malloc_dbg_impl+0x0000000000000039
        7ffd02401049 MSVCR120D!_nh_malloc_dbg+0x0000000000000049
        7ffd02400d79 MSVCR120D!_malloc_dbg+0x0000000000000039
        7ffd024015ac MSVCR120D!realloc_help+0x000000000000005c
        7ffd024013e5 MSVCR120D!_realloc_dbg+0x0000000000000055
        7ffd0241837e MSVCR120D!realloc+0x000000000000002e
        7ffcf4642655 rubyprov!enc_table_expand+0x0000000000000055
        7ffcf4641d4e rubyprov!rb_enc_init+0x000000000000000e
        7ffcf4641753 rubyprov!rb_utf8_encoding+0x0000000000000013
        7ffcf46680d3 rubyprov!rb_w32_sysinit+0x0000000000000043
        7ffcf45acd5d rubyprov!ruby_sysinit+0x000000000000001d
        
0:004> !heap -p -a 0x000000E48B52FAD0
    address 000000e48b52fad0 found in
    _HEAP @ e483840000
              HEAP_ENTRY Size Prev Flags            UserPtr UserSize - state
        000000e48b52fa70 0009 0000  [00]   000000e48b52faa0    00064 - (busy)
        7ffd20358b04 ntdll!RtlpCallInterceptRoutine+0x0000000000000040
        7ffd20329f36 ntdll!RtlAllocateHeap+0x0000000000079836
        7ffd023eb4cd MSVCR120D!_heap_alloc_base+0x000000000000005d
        7ffd02400b1b MSVCR120D!_heap_alloc_dbg_impl+0x000000000000027b
        7ffd024010b9 MSVCR120D!_nh_malloc_dbg_impl+0x0000000000000039
        7ffd02401049 MSVCR120D!_nh_malloc_dbg+0x0000000000000049
        7ffd02401e9a MSVCR120D!malloc+0x000000000000002a
        7ffcf4605d57 rubyprov!objspace_xmalloc+0x0000000000000037
        7ffcf45f2caa rubyprov!ruby_xmalloc+0x000000000000001a
        7ffcf460da32 rubyprov!new_entry+0x0000000000000022
        7ffcf460db36 rubyprov!add_direct+0x0000000000000086
        7ffcf460b075 rubyprov!st_insert+0x0000000000000105
        7ffcf457ed5e rubyprov!rb_method_entry_make+0x000000000000056e
        7ffcf4569049 rubyprov!rb_add_method+0x0000000000000059
        7ffcf4568ef3 rubyprov!rb_add_method_cfunc+0x0000000000000083
        7ffcf45557b1 rubyprov!rb_define_method+0x0000000000000041
        7ffcf46ab54f rubyprov!Init_Time+0x000000000000069f
        7ffcf46b7fa0 rubyprov!rb_call_inits+0x0000000000000090
        7ffcf458f966 rubyprov!ruby_setup+0x00000000000000c6

0:004> !heap -p -a 0x000000E48B4F08F0
    address 000000e48b4f08f0 found in
    _HEAP @ e483840000
              HEAP_ENTRY Size Prev Flags            UserPtr UserSize - state
        000000e48b4f0890 0009 0000  [00]   000000e48b4f08c0    00064 - (busy)
        7ffd20358b04 ntdll!RtlpCallInterceptRoutine+0x0000000000000040
        7ffd20329f36 ntdll!RtlAllocateHeap+0x0000000000079836
        7ffd023eb4cd MSVCR120D!_heap_alloc_base+0x000000000000005d
        7ffd02400b1b MSVCR120D!_heap_alloc_dbg_impl+0x000000000000027b
        7ffd024010b9 MSVCR120D!_nh_malloc_dbg_impl+0x0000000000000039
        7ffd02401049 MSVCR120D!_nh_malloc_dbg+0x0000000000000049
        7ffd02401e9a MSVCR120D!malloc+0x000000000000002a
        7ffcf4605d57 rubyprov!objspace_xmalloc+0x0000000000000037
        7ffcf45f2caa rubyprov!ruby_xmalloc+0x000000000000001a
        7ffcf460da32 rubyprov!new_entry+0x0000000000000022
        7ffcf460db36 rubyprov!add_direct+0x0000000000000086
        7ffcf460b709 rubyprov!st_update+0x0000000000000319
        7ffcf461abcb rubyprov!tbl_update+0x000000000000008b
        7ffcf46192e8 rubyprov!rb_hash_aset+0x00000000000000b8
        7ffcf456808d rubyprov!rb_vm_add_root_module+0x000000000000003d
        7ffcf4555255 rubyprov!rb_define_class+0x0000000000000105
        7ffcf45d067d rubyprov!Init_IO+0x000000000000025d
        7ffcf46b7f96 rubyprov!rb_call_inits+0x0000000000000086
        7ffcf458f966 rubyprov!ruby_setup+0x00000000000000c6