We ran into the issue where on survey activation with closed-access mode and public registration allowed, a database error was thrown if the survey had been activated in open access mode previously. The database error stated that the finaltokens table already existed. Digging deeper, the SurveyAccessModeService->newParticipantTable method was called twice under these exact conditions, once via SurveyActivate->activate and once via SurveyAccessModeService->changeAccessMode. Obviously on the second call the table already existed and $survey->hasTokensTable should have caught that, but no.

So long story short, the tableExists helper in application/helpers/common_helper.php used cached results on the second call, meaning $survey->hasTokensTable was still false and an unsuccessful attempt was made to create the finaltokens table once more.