I don't know why but my mind ignored how it only happens when turning right until I watched the videos. That has to be one of the oddest behaviors I've ever seen! I've seen bad servo's have some weird side effects but this takes the cake! Having the kill switch reset after turning left is the most baffling.

Normally I'd say there's a servo giving off some sort of feedback causing havoc, seen that sort of thing before. But that's usually constant and this isn't. Plus your linkage seems to be adjusted well as the servo's don't seem to be fighting each other at all. One or more of the servo's still gotta be doing something to effect it though. Do the normal shuffling of the servo leads to isolate the offender, plug in other servo's, try the offender in a different channel, etc. And please let us know how you make out!