Forwarding this bug report from Lance Navor:
Earlier, I successfully recreated some of the problems that I likely encountered in the design process (attached herewith are screenshots and links to screen recordings). I navigated my way to a previous version of the project near the timestamp of the screenshot I attached in my documentation (see "Screenshot_1_highlighted"). From the image, I couldn't tell if I was at #d940fe24 or #eb760986, but either way, it can be seen that J3 is missing from the preview (note that I did not click "Restore Version"). I then navigated to another previous version of my project (version history ID #93f31d5b; see "Screenshot_2") to find a version where J3 was present, again not clicking "Restore Version". I then went back and previewed version #d940fe24 (see "Screenshot_3"), and it can be seen that while J3 has indeed reappeared in the PCB view, new discrepancies have presented themselves (comparing "Screenshot_1_highlighted" with "Screenshot_3").