Hi Jim,
It would help if you freeze the tracks of a song project that has the issue and then post the MGU or SGU song file so others can verify the issue or offer suggestions to fix the issue.
An alternative would be to send the song file to support@pgmusic.com along with a description of which bars the issue happens.
I have not experienced the issue and do not remember seeing any posts complaining of gaps in the Ohs & Ahs RealTracks.
Also, if you haven't done so, you may want to download and install build 625 of Band-in-a-Box and the February 11, 2019 RealTracks update. The BiaB build 625 update is available
+++ HERE +++. The RealTracks update is available
+++ HERE +++