Currently the timebase set for lyrics track i.e. either seconds or beats is applied to all the lyrics tracks including global and all instrument lyrics tracks.
It would be super useful if S1 allowed global lyrics track timebase to be different from instrument lyrics track timebase.
For example you could have global lyrics track representing lyrics of the Lead Vocal Performance and have it set to timebase seconds, because you don't want to timestretch the lead vocals and its lyrics with the changing tempo track, but you would want the instrument parts and its lyrics track to be on musical timebase and sync to tempo changes.
This feature would be possible if each lyrics track had its separate expandable/collapsible lane in the global arrangement window and an icon for setting the individual timebase on each lane for that lyrics track, which has been requested in the following feature request :