I ran into this exact issue while trying to equip one of my outfits that had Stevie Standard’s DefaultFallBackMood applied onto it.
In my case, because the fallback mood wasn’t given when I acquired the dynamic head, it renders the outfit unusable.
I do recall this is due to a related issue with the editor in general that was brought up back on July 16th, where it would not equip the other items in the outfit that the user does own.
When changing into the outfit, there were no failed network responses or console warnings.
I checked the console, and it is only warning me that I have blocked escv2 at a browser level. That should not impact anything, I just can’t stand being tracked.
It may be similar to the one you linked, I’ll watch for anything there to see if it’s fixed.