When editing Closed Captions, making a change undoes a prior change

As stated in title.

I imported an SCC file that needed some revisions, such as changing some characters or spaces. After making some changes and clicking out, I realized the Captions window would shift up or down, and after some time I noticed this was because a line I had changed before this one would change back to its original state, sometimes adding an extra line of text or sometimes removing it. After working some more I realized this wasn't limited to the last thing I edited, for example, I changed a line of text, then made two more changes. Once done with this third (overall) change, I noticed the first one would revert back to the original text. It would also disappear from my History. I would go back and fix it, then correct line number 4, then line number 5, and again, the first one would revert back. Any help would be appreaciated but I think it's a bug and wanted to bring it to your attention. This also happened on the latest version of Premiere Pro, not just in this Beta.

Steps to reproduce:
    1. ...
 
Result: ...
Expected: ...
 
System info
    Application: Premiere Pro (Beta) v15.4.0.33
    OS: Windows v10.0.19042, RAM: 31.93 GB, CPUs (logical): 12