It's not a glitch. It's PD pre-rendering a section of your timeline either because of a setting or because you clicked Yes when it asked you to pre-render a section because the video playback was choppy.
For the first case, disable this option:
In the second case, you may have chosen Yes at some point when you were presented with this message screen:
If you see it again, choose No.
Again, these are related to the UHD preview quality setting and staying at Full HD or lower will prevent the issue from appearing without warning.
It's also possible that you clicked on the Render Preview button at the top right end of the timeline, so don't do that either:
You may also want to delete all the temporary files to ensure that they won't interfere with your future editing. See this
post for details.
A final option is to let the rendering process finish so that you can actually preview the project in real time and at UHD quality, although in my experience it's better to use Range Select and produce that specific section and then bring in the produced clip to replace the original timeline content
This message was edited 1 time. Last update was at Dec 27. 2022 12:33