Please boot with disabled caches, and install the 46.3 release of the 68040.library. Then please run "ShowConfig" and post the output here. Then also run "MuScan" from the MMULib archive, and also post the output here.
It seems that some part of the host memory of your system does not support bursting (probably?). If so, one can, in principle, disable the caches for the affected memory selectively, but for that, we first have to find out what is in this system.
For me, this looks like a hardware issue at this point.