Yeah, Reverence. It is a funky program in the way it opens in a saved Project and sometimes very clunky the way it behaves when opening the various sound files - and your experience is typical. What I would do is create a preset within Rev if you can - and save it so it can be recalled to the project. And actually, try to find WHERE REV stores these presets, this might help you someday.
Further, at one time I started searching for the Preset files (when they stopped loading) and found them in two places. Rev didn’t seem to know where they were. I never could understand this, how a program as seemingly complex as Rev did/does not have the option for the user to determine the save folders. Typically I use either a Wave IR verb or SIR2 but not because REV didn’t sound good, only because it was so difficult to control. Best of luck.