Nick,
go into Plug-in Manager, and make sure you have highlighted the presumed to be incompatible H910 plug-in… and then click on the reset and scan selection option… the plug-in manager will then rescan the item, and hopefully the blue tick will include the words “successfully validated” … this isn’t a Eventide problem it’s an godsend from Apple, bless there hearts, but I have to do this many a time with other plug-in manufacturers – and I have Eventide, Soundtoys, Arturia, Korg, Fabfilter, East West, Heavyocity, Korg and Native Instrument’s… all of which I have had to do the dance of the reset and scan.
I am user, not a member of the Eventide help crew… so if you still got an issue… maybe contact them direct via email…