Jumping to interrupt spells works pretty well because most spells either have a short execution time or can't be cast on the run, so there's rarely any conflict between jumping and interrupting. Otoh, some bard songs have very long execution times and can be cast on the run, so if you're in a place with uneven terrain, you will quite often want to jump but be unable to do so without interrupting your song. Is there a way around this that I'm not aware of? If not, it would be nice if there were some way to prevent this conflict.
Anytime you perform an action that brings up a progress bar, jumping will interrupt it while the progress bar is up. There's no way around it.
Not 100% sure, but iirc, when bard songs were first implemented, there was no way to interrupt them, including jump, and that was fixed. I'm not really sure what the best solution would be since you obviously should have some way to interrupt songs. Maybe if stop singing was bindable and bound to the same key as jump by default, or something like that. I doubt it's an issue for that many people, but with atonal aria working properly now, it's more of an issue than it used to be.
I wanted to chime in and agree with Lazlo. Bard was intended to be mobile, and jumping is the only way through some terrain we encounter while fighting. It is very frustrating to charge up a song only to lose it because you are trying to maintain a distance.