Fortiguard spam URI false positives, have they changed something?

One of my customers was having far too many false positives being identified by fortiguard spam URI. I see in our logs that 'spam URI' detections stopped on the 18th March, clearly Fortiguard have done something as no config changes were made to FML.

Did anyone else have false positive problems with 'fortiguard spam URI' or know what happened?

I did have a ticket open on this but TAC basically just shrugged their shoulders and said sorry it's fortiguard and we can't do anything.