Possibly Solved?—(edit…nope)
I’ve been having the identical issue with several files. After reading this post I turned off “Snap to Grid” (I don’t use Stacks). After closing that Preference window the offending file still wouldn’t move out of the top right (directly over where I’ve always kept my hard drive icon).
I tried it again, turning it on and off, still no luck. Finally, I turned Snap to Grid back on and then gave a slight “wiggle” to “Grid Spacing”, just kind of shifting my desktop file spacing back and forth a tiny bit. Dunno if I’m actually even on a slightly different spacing than I was before, but it WORKED! I was immediately able to drag the offending file away and place it anywhere on the desktop. I also used “Clean Up” and everything spaced out normally. Shut down, restarted, but so far it’s still working fine. I’ve been trying to replicate the issue now but cannot and all those tools are working normally (Snap to Grid, Grid Spacing, Icon Size, etc). Try "wiggling" and report back?
PS—another thing about when the issue was happening—if the file was moved anywhere else on the desktop it kept snapping back to the top right. However, it WOULD let me place the item into a folder, any folder. But, the moment I removed it from that folder no matter where I placed it, it once again snapped to the top right. Just something for all of us with this issue to also try to help narrow down the bug.
Sorry—I re-read the OP’s post and it looks like they tried some of this too. Dunno; maybe it will start with me again. Wiggle EVERYTHING in View Options and see what happens.