I had the same problem with my wife's TA chainrings. The chain would "skate" on the tips of the middle chainring teeth instead of dropping over. I cured the problem by filing the inside edge of the teeth with a flat file. The aluminum these rings are made of is soft and files down quickly. It won't take a lot of work to thin them, and the strength of the teeth where the chain runs will not be compromised.
I also moved the chainline outward 1.5 mm with a bottom bracket spacer, but I think filing the teeth was the primary cure.