>   64 65 66 67 68 69 6a 6b
>   6c 6d 6e 6f 70 71 72 73
>   74 75 76 6b 00 00 00 00
>   20 00 00 cd 22 80 01 b8

tailmagic corrupted?

we got:
defghijklmnopqrstuv | k\0\0\0\0 \0\0\cd\22\80\01\b8

we expect:
1234567890abcdefghijklmnopqrstuv | xyz

OverflowCheck is 32 bytes, so xyz are not included in the buffer.

i dont think that the zmagic got corrupted.

cinap