More information would be needed to really help. Things like is the MIDI song generated in BiaB or imported into BiaB?
How did you save and export the song? ETC.

However the first thing that I would look at is song settings for the start of the song, the numbers of measures in the song, and how many times the song is looped; see attached picture. If that doesn't help trying the return to factory settings/most under the options menu.

I hope this helps and good luck.

Attached Files (Click to download or enlarge) (Only available when you are logged in)
1-settings.jpg (80.87 KB, 128 downloads)

When you are at the checkout line and they ask if you found everything say "Why, are you hiding stuff?"

64 bit Win 10 Pro, the latest BiaB/RB, Roland Octa-Capture audio interface, a ton of software/hardware