I did play around with action height quite a bit on this guitar when I first got it. I adjusted the action height with full string/spring tension. Wonder if I damaged the studs?

Make sure your locknut isn't slipping. Hook up to a tuner and push on the strings behind the locknut and see if they go sharp.

This damages the knife edge on the trem not the studs and if you did it a lot it's possible the knife edge is shot.

I've heard opinions all over the place on that matter, so I wasn't sure. I'll pull the trem and give the knife edges a look over.

I keep this guitar at work, so I'll give that a look over tomorrow. But even if the nut was slipping, would it make sense that it goes back in perfect tune after a dive?

The Ibanez Prestige model hand book that came with my RG1550ML is the source of that statement. It says changing action with string/spring tension damages the knife edges. I have always pulled the tremolo springs and the strings when adjusting action so I don't know for a fact how it reacts. I've always done that on all my guitar equipped with a free floating system. Good luck bro!

Add another string for more return tension..

I've always adjusted the height with full tension and never had a problem. But like you said, each has their own opinion on that. But i would check the knife edges and the studs.

+1 been playing on Floyd since the 90s and never took tension off to adjust action. Makes no sense to, you wont be able to see/feel where you like it

I don't understand how people can think that way. If a guitar has a set of .010 gauge strings on it there is roughly 103lbs. of tension on it. With this much force being exerted how can anyone believe turning a metal screw against a metal knife edge will have no affect? Like I said I have never adjusted my action with any tension on a Floyd Rose bridge so I can't say for sure that there will be damage but physics supports the theory. I have been playing on the Floyd Rose Original since 1986 and I still have my first Floyd unit and the Kramer Baretta it came on. It still works just as good as the day I got it and I have to believe it's because I've always took every and any precaution to keep it that way.

Never had a problem in over 20 years of playing and my first real Floyd is from when they put "Original" on the plate and it's still sharp and always returns to pitch. I do actually lube the knife edges too though

Same here.

I always dive the trem so the studs turn a little smoother when adjusting the action

Physics also supports building a violin to "Stradivarius" specs and when you play it the tone sucks. No problem for the Floyd screws to be turned to under tension.

You checked to make sure the nut is screwed tightly to the neck correct? Any burrs in the saddles of the affected strings that could be grabbing them a bit on pull ups? Try some big bends nut sauce or equivalent on the knife edges. Chapstick is good in a pinch but something a little less viscous is better.