I imagine you could edit the sidebar ID via SQL. I’m guessing that the sidebars are currently being sorted by their ID number.
I found a _cache.php file hidden on my hosting account (Bluehost) on a site I haven’t touched in over a year. Deleted the file and everything seems to be okay so far. (It’s been 2 hours).
I’m having this same problem. If you find a solution PLEASE let me know about it.