Edge Zero help

[Panacea224]

I bought a new RGD2127z recently (some of you may have seen my NGD thread) and I really like the guitar but I have been having some difficulty getting it to stay in tune. I have been using floyd rose bridges for about 8 years now but I can't figure out what is going on: when I got it it was sort of tuned to A standard, it was a little low for my tastes so I tuned it to half step down from standard. It was fine for a while, the low B would go a little out of tune but that was it. Now, for the last few days it seems after just a couple of minutes of playing it goes out of tune and not just the low B now it's most of the strings. I checked the intonation and it seems fine (though this is the first time I have had to do that). The bridge is at it's zero point and the neck appears straight as best as I can tell. Does anyone have any ideas as to what could be the problem and how to fix it? Thanks guys.