According to this:
Apple does not yet support the X-T30 II. There are some options you can try.
Use this (it is free) to convert the raw files to TIFF, which you can then edit in your current editor.
Use an EXIF editor to change the camera name in the raf’s exif tags to X-T30 — version one — and then the Apple support should be there. I do not recommend this other than as a last choice option.
I am hoping this time does work for you. I have heard when this issue happens somewhat seemingly randomly, there is a problem with the power supply, but I have not yet heard of this happening only because of updates.
Okay, I will give it a try for at least a week (today is the second day). I will try again tomorrow after a week, which totals 10 days. That should be sufficient, I hope... Thanks anyway for your suggestions so far!