Also, I'm surprised that CSTM and FSTM would be the same, since I added a field at the beginning of a struct that wasn't there before. Someone might need to take a look at the code and see if they can get it working.
I'm pretty sure the same thing that you did to RSTM is identical to the problem that FSTM has. But as for CSTM, it doesn't have any clicking noise, so it doesn't seem to have any issue in it's encoding.
I just need to find where the code is for encoding CSTMs and FSTMs, then I'll experiment around with them and see if I can fix the issue.