I was just playing about with the “Generate Timestamps” function, and I found that in order to generate timestamps properly you have to first hit the “Regenerate Lesson” button, otherwise the timestamps won’t generate properly.
As far as I can tell, this is the only real function of the “Regenerate Lesson” button. It doesn’t seem to do anything else.
Here’s a thread where I explain how to do it:
https://forum.lingq.com/t/how-to-generate-timestamps-that-actually-work/214946/4