I had the same thing. I did not pass the inital test but received this morning an invite for the digita interview.
Working in tech, I had a suspicion that something must be wrong and I emailed support.
TUI's support confirmed that the system they are using had an update, causing an issue where it progesses some ( cannot confirm if all ) candidates to the next stage, without checking their status. Thats all I know and hope it helps!
Makes me wonder tho if there could have been an issue with the test system. I know it is not related to this but that thought has slipped my mind.