Roland Cloud issues with Mainstage

MacBook Pro, Mojave, SSD, 16G internal RAM.

I subscribed to Roland Cloud about 2 months ago because I like the JV series stuff, mostly. I also have used the D50 and SoundCanvas synths (mostly because all of those use much less memory).

My problem is that certain RC synths (JV, especially) cause MS to hang up in loading ONLY when connected to an external audio source. I have tried this out on both a PreSonus Firebox and a Scarlitt Focusrite. It reacts the same way on both. However, when I disconnect them, the file opens up normally. If I reconnect the external devices, after a few tries, it will finally work...but only if the file is already open.

For instance, I can add JV synths to my MS patches and everything works fine once it's open and working...even connected to an external audio device. I save the file and close it. When I go to re-open it, it hangs up at the "Setting up file" stage. So I need to force quit (I've waiting for 20 minutes at one point). If I then disconnect the external audio device, and re-open the same file, it will open normally. Then, while it's opened, I reconnect the external audio device, and have to go to the audio preferences and manually choose the PreSonus/Focusrite...sometimes right away and sometimes after several force closings/re-openings, it finally works. BTW, with the PreSonus I'm using a Mio USB/MIDI converter...that seems to have the same effect...though reconnecting it, once the file is open, is less of a hassle.

I've talked to Roland and they say they haven't heard of issues, but then they also said they don't actively support MainStage...so there's that.

I would chalk this ALL up to RolandCloud, except that this doesn't happen when I have just D50 instances in my MainStage patches. It's pretty much the JV and others.

I've messed with the audio setup in MS and turned it to "System," trying to get it to adjust based on my Mac OS (which has no problem recognizing the other devices). That doesn't work.

The only thing I haven't messed with is sample rate. It's currently set to 44.1k/24 bit. I can't imagine that the synths in Roland would be different sampling rates?

HELP! It's aggravating as ****. I can OBVs get rid of Roland...but I want to exhaust all possibilities that it is me and not them.