I’ve also reproduced the issue in my setup using the attached projects.
However, removing the unused imports did not fix the issue, in my case. What actually worked was to remove both the activities and then add them back to the project. By doing so, compilation was successful.
I’ve tried replicating the bug using newly created libraries and projects, but I couldn’t. They all worked as expected in my setup, which indicates this issue also has something to do with the upgrade.
I’ve opened a bug to track this issue.
Thank you for the provided detailed description.