Cannot hide "running tests" pop up after getting FATAL error "Executable path is empty. ()"

The notification pop-up in "Progress details" won't hide even by closing it manually, after getting an error

FATAL "Executable path is empty. (qquickloader)" 

This happens when a test's build fails, so the test executable is not found. If the pop-up is closed manually the "Test results" tab logs that the test is cancelled by the user, however the pop-up stays.