The usual reason for this is slight tape path alignment errors on one or other of the cameras, possibly coupled with slight head wear. The quickest way to check is to beg/borrow another (preferably newish) camera and check them on that. The best way to check them is with the manufacturer's test software & alignment tape which will check the path and error rate from the heads.
you also might like to check out the recording properties on the Cannon tape - although tapes *should* be transferable between camcorders if recorded in Standard Play (SP) mode there is often quite a difference between camcorders in Long Play (LP) or other non standard mode
If it comes up with a message 'incompatible media type' or some such, chances are the recording was made in one of Canon's extended modes. These allow something like four or eight hours' recording on a standard DV tape and afaik can only be replayed on a Canon camera with these features.
one further thought occurred to me - are both cameras of the same TV standard - that is are they both PAL or is one of them an NTSC (American) camcorder.