Horizontal Frames causing mayhem

Hello all,

In my efforts to add large time signatures, I've been using the horizontal frame and graphic technique outlined here:

https://musescore.org/en/node/298789

While for the most part it works, the horizontal frames are a nightmare. If they are inserted mid page, they create a system break that can't be reversed. If they are inserted at end of page and then moved, they can often gray out and become fixed with no way to adjust them after placed. Other times they will show up on the wrong page, different from where they are placed. And just now I've discovered on an export that for no discernible reason one has decided to disappear from the PDF.

Anyone know how I can avoid these issues? It's a hassle at best and ruins the file at worst.

See attached score for examples.