@drj It's an awful long time ago that I wrote any 68000 assembler - this was during the development of the QL which actually used a 68008.
One booby trap I seem to recall was to do with moving more than one byte at a time via an A register used as a pointer and containing an odd number. Didn't work at all, but I have a vague feeling that this got "fixed" (at the cost of additional bus cycles) in later processors?