Did your snap settings get saved into that base file too? A guy I used to work with had this same thing happen on a strip mall project and it drove him nuts for a week. He'd place the title block, it would look fine, then the next time he opened the sheet it was off again. Turned out there were like forty stray nodes scattered around from some survey file someone pasted in years back. He ended up making a "wipe" layer and just deleting everything outside the print area before he starts any layout now. Takes him five minutes up front but saves him hours of zooming in and cussing.

Getting 6 issues at once for around $17 meant I could actually remember what happened is the real point here, the story holds together way better when you read it in one go instead of dragging it out over half a year. I did the floppy thing for years on a few books and half the time I'd forget a side character or a plot thread by the time the next one dropped. Wait for the trade unless it's a book you truly can't stand waiting on.