I am creating subtitles for a video, using the subtitle creation tool. Everything works fine for a while, then when I want to add a new subtitle, it doesn’t add the subtitle to the cursor position, but to the beginning of the subtitle list. With negative timecodes!
As an experiment, you could try to close, and then re-open Shotcut and see if it keeps happening.
The next time it happens, it would be helpful if you could save the application log and upload it here for me to inspect. There might be a clue in the log.