OK, we did follow up via email. The problem is that this song is a whole 50 minute set with lyrics for all these songs. The iOS text editor component seems to have memory issues when editing such a large amount of lyrics. The crash happens in iOS components and not in Stage Traxx code so the chance that I can fix this with modifications to Stage Traxx code is rather small.
Best workaround is to split the set into separate songs and use Autoplay to play the set as a whole.