Note: I believe this is an intended feature of the launcher, but...
So, yesterday, I logged onto the Technic launcher to go on tekkit lite, but to my surprise, 0.6.0 had disappeared, with 0.5.9 the newest version and saying 'Latest'. When I logged on, and opened up my world, I found parts corrupted and missing, and dimensional anchors everywhere looking like they had spread out of my chunk loading room. I have no idea of what had happened, except that by downgrading mods had changed ID's. Although, I had nothing on the roof that could have turned into dimensional anchors... Please investigate this.