Hey there,
first of thank you again for the trainings.
It happened to me now the second time in 2 weeks that during my training, i was changing songs (which normally works fine, i just switch back to the app and go on with training) and the app closed down; all training progress of the day lost had to start the workout again and skip through to my actual work set.
Not a huge problem but maybe something that‘s easy to fix. I use on newest iOS
Best & have a good day :)