I was trapped by the same bug, can’t get rid of it by following attemps:

• turn on safe mode
• restart the ipad (air 2)
• update the ios to 13.3.1
• click another beta testlink
• hold the app icon button to send beta feedback (which in turn jump to test flight telling like “the app does not exist”)

And ‘m sure that the yellow dot aside means the app is now a beta version.