I am also having this problem.
To be clear I'm getting a 500 error, but it when I try to create a test lab, and then try to delete the test. I'm getting the following message
This is a test copy of Adventure \"?????\". It is for testing use only.
Note: There have been changes made to the source Adventure since this Test Adventure was created. To see those changes, click \"Delete Test\" and then recreate the Test from the Source Adventure.
When I then try to delete the test it sends me to a 500 error.