You're welcome and thanks for looking into this for me. I have version 8.56, which I only purchased on 7/15/20. Is there an update available?
Also, I added the Carleton track as a new track again, placing it on top, which worked fine until I tried to split another track. (I thought I had gotten them all but found two tracks "Hu" and "Jo and Terrence" that I missed. Did you get the same switch to vertical? I wonder is this has to do with the version.
...argg. I just split that section of the project to create a left and right side, to isolate the 5x5 splits as the right side. On the version saved as the left side, I deleted all of the would-be 5x5 clips and still had the sequence flip to vertical when I un-muted the tracks on the left side and made them visible. What established the AR for the sequence in the first place and what am I doing to make it change? Thanks. -cwj