I posted this on the forum, but have gotten no useful response. In our production DNN 9.2.1 CE site (which has always been the community edition, originally v4.x and updated regularly), on the File Manager screen we are now getting the error:

Error: Digital Asset Management is currently unavailable. DotNetNuke.Services.Exceptions.ModuleLoadException: Sequence contains more than one matching element

From doing a db and filesystem restore to a dev environment and running a debug version of the DigitalAsset module, the error is happening in Factory.cs where it explicitly calls .Single() to get the controller for the community edition instead of .First(). We did not make any DNN updates or install any new modules when the error began.

Where are the digital asset controllers loaded, and how can I prevent the errant second controller from loading?