Update.

I started by cleaning the mouth of my bottle of Rodinal. Dried up Rodinal had coated this area. I also cleaned out the small beaker I measure it with. I often don't do this between films but I cleaning right after I mixed the developer with water. I also tapped the tank after the first 30 sec of development as well as before.

I then used water as stop instead of stop bath. I continued with the agitation time of 10 sec every minute but with far more vigorous agitation. So far all of these problems have resolved.

This has certainly made me more cautious when developing my film.