When you change your audio output settings (such as switching from Speakers to Headphones), it will not change alongside your computer, and you have to exit and reopen Shotcut in order for Shotcut’s output to be changed.
You did not specify your operating system. That is unfortunately true on Windows, but not macOS or Linux with PulseAudio. I know Windows users typically forget there are other operating systems. Unfortunately, it is not an easy fix due to a bug in a library we use:
This suggests there may be a fix in v2.0.6 but we are still using v2.0.5. I will try the new version and see if it works.
We would have to try to fix their library, but we already have so much to do. And meanwhile there is a simple workaround that you have found: save and restart.
Yep, I just confirmed the latest version 2.0.10 of SDL fixes this. I will update it soon.
This is fixed for the next version 19.12.
I am sorry, but the change to fix this is going to be reversed in the next version 19.12.31 because it caused audio crackling for some users. I will revisit it again after the next release.