I think you are saying the anti-derail (more common term) feature fails to throw the turnout to go straight. At all? Moves partially? Or just not consistent?
If it is consistent with the switch being used, I'd look at the track triggering for an issue. It could be dirty wheels, track or even the traction tire not completing the circuit...? You don't say how you detect/trigger them. If consistently missing both ways, look to wiring, connections, and the turnout itself.
You shouldn't have power issues really; but note a heavy track draw may weaken what is available for the accessories constants. E.g. you'd get less flicker (imagine a lamp vs turnout coil) from two power supplies vs one where track and accessories share output, even if it's hi-output (there are exceptions... basically some supplies are actually 2 supplies in one package.)
So if you are pushing the Zs limits that could be it
