Unfortunately, I’m seeing far more failures on my machine with Firefox to be sure what you’re seeing, when you run these tests. However, I was able to address one of the areas that I saw multiple sleeps added and made the code more robust with Waits. The changes below to the file at .../pgadmin4/web/pgadmin/feature_tests/xss_checks_file_manager_test.py specifically wait for the element to be detached off the DOM and then to be reattached before retrieving any more attributes.
instantiate the element using an anonymous function that takes the selector method
add a new reusable method to the page object that waits for attach/detach
I’ve attached my changes as the file 0002-RM_3270_v5.patch for you to compare. If you’re unable to get some of these other issues, let me know and we can get through this!