not all muse sounds displaying in musescore

Hi everyone. I'm running on Musescore 4.4.4, and I'm working on a project that is reliant on the sounds we get from Muse Sounds. When I was working on it this afternoon, everything was fine: all of the Muse Sounds I have were working perfectly well, everything was displaying and sounded as it should. But partway through the piece, the sound on the piano part needs to change, so I was experimenting with different sounds (I couldn't really find what I wanted, but that's beside the point) and for some reason, one of the sounds I tried and decided I didn't want continued to play, even though I'd removed the "change instrument" text from that stave and even the notation in those bars. Thankfully, because I hadn't saved that project yet today, I was able to close and reopen the file to fix the issue, which took me back to how I'd originally had it when I started today.

This is where the Muse Sounds issue lies: when I opened the project up again, I had to change a couple of instruments that I'd changed earlier (i changed finger snap and hand clap for two marching snare parts), but when I went to put the notation in one these two snare parts, I found that the notation options were completely different to earlier. Delving further, I went into the mixer and found that at least half of my Muse Sounds weren't available, including the Muse Drumline sounds which I depend on for this piece (those sounds are why I chose to switch to the marching snare parts in the first place).

I've also been having issues with keeping my Muse Sounds downloaded, as they have a habit of un-downloading (is that a word? eh you know what I mean lol) themselves, and then taking several tries to re-download again, although for some reason they still work in Musescore, so I'm not sure what 's happening there. Either way, all of the free Muse Sounds (which are all I use, I'm not spending money on sounds) are downloaded, so I don't get why they won't show up in Musescore.

I've checked the same thing on other projects as well, and the same thing's happening there: half of my Muse Sounds don't show up. I've included screenshots of everything I think might be relevant (the mixer options, Muse Sampler, Muse Hub library), so if you have any idea what's going on and know how to fix it, please let me know, and if there's anything else you need to see or know from me, then please ask.

Thank you :)