PTP400 upgrade/negotiation mismatch??

something curius happened to me couple of days ago.
ptp400 lite M-----ptp400 lite S—CMM—BHs+APs
when upgrade ptp400 to full and reboot started packet loss/mismatch configuration simtoms, betwin ptp400 S and the CMM
I tried every negotiation on both devices but nothing. Changed patch cord, and cmm port, nothing.
Today I put a cisco switch in the middle and that solved the problem, but still dont know why…