“Save As” deleted elements on my master page?

I was modifying an existing plot today. I was experimenting, so I thought it would be a good idea to “save as” so I could come back to my starting point if I didn’t end up liking the changes. I did a save as on my new changes to a different name, and did a save as on my old file (because eventually my new changes would take the original file name). In both cases, the act of doing “save as” deleted some or all of the elements on my root master page. I lost some significant amount of work, as various items had actions attached, etc. When I go to load a plot and select the file to load, the thumbnail actually renders the plot correctly, so I’m hoping maybe my elements aren’t lost but just rendering incorrectly?? They don’t show up on the plot or in simulation. I can send you some files if you want to take a look.