Thanks, @Nechoj!
However, the code shown here is only a minimal reproducing example. It uses choose only incidentially. The original project plays notes from arrays that are generated before any live loop starts.
For details on that project, see this forum thread (which you already commented on 
). Code and documentation are linked there. The recorded track there is already corrected through a shortened first note.
EDIT: it is the bass live loop that is affected there. bass_delay is the correction.