Here’s a link to a version that has the problem (just before merging the vertices).
https://drive.google.com/file/d/1s5B8rcJA3uOUM0SY-m5kHB97bFl2TSeG/view?usp=drive_link
I discovered that deleting the edge between the merged vertices and then recreating it and the faces results in working edge loops. That indicates there’s something wrong with that edge, but I can’t tell what. I looked for extra faces attached to it, but I could see any.
