In the editor this B Part adequately represents the phrasing of the fiddle tune “Morg Williams’ Cotillion” from Spencer and Rains. However after saving changes the switch back to 4/4 after the bar of 2/4 is not present, and the rest of the B Part remains 2/4. In the editor the part does play just fine.
Thank you so much for the bug report! I’ll have this fixed sometime next week.
This bug should be fixed now (in v415.7). You’ll have to edit the song and change the cells back to 4/4, but it should then save properly. Let me know if you run into any issues, and fingers crossed that I didn’t introduce a new bug while trying to fix this one. 
(Keeping things backwards-compatible makes things more complex than they might seem!)
Thanks again for catching this!