I upgraded a working solution to Xamarin v126.96.36.199655 and also updated the Android target framework to 9.0
Now when I try a clean build I get 4 errors like:
error APT0000: No resource identifier found for attribute 'layout_behavior' in package 'com....'
All 4 variants of the error refer to the same attribute in different files that are no directly part of the project.
Tried various forms of deleting everything under obj, restarting Visual Studio, etc, etc,