There was a bug in chdman that caused things to be compressed in a different order across OS's causing the chd file itself to differ. The chd is still good but could be different than one made on another OS.
I just converted several v4 CHDs to v5 using chdman version 0.146u2 and compared the results to the ones I converted from v4 to pre 0.146u2 v5 to 0.146u2 v5. The results are seem to be the same. So, if someone converted to v5 before 0.146u2, their chds may differ than someone else's chd file made with chdman 0.146u2.
The chd's on my D Drive were double converted. The chds on the F drive were just converted from v4 chds just for comparison.