In older versions (7.18) doing the following worked
But under 7.82 the index is broken, e.g. add a unique index and then add two records with different values and it fails with key violation.
Fortunately I can work around it by changing AddIndex to IndexDefs.Add(…) and then create/open the table (but now just have to try and find all of the places in the code people might have done it the way above…)
Thought you should know as my guess is that the new behavior might be unintended.