Hello T.
I may have spotted a small logical bug in spat5.oper concerning reverb gains of sources when changing their assignment to a room. please have a look at the attached patch.
logical bug in spat5.oper_.maxpat (5.1 KB)
Max/MSP version: 8.0.5
Tested on SPAT version: 5.1.0 & 5.1.1