There's no such thing as "older" or "newer" VCRs, regarding the way the TBC reacts. That's just hogwash on their part.
The AVT-8710 was fine all the way until 2010. The newest S-VHS VCRs are from 2005 and before. What they say is therefore illogical nonsense.
Every AVT-8710 that flakes on the menu has flaked on video footage, too.
Sometimes the VCR menu will pulse, because menu video signals are not always 100% standard to the NTSC or PAL specs, but it won't go ape wild like defective AVT-8710 units do. You can see this easily by comparing multiple TBCs, including known-good AVT-8710 models, against it.