a7RCII weirdness: Yesterday, after a few normally saved shots, my a7rcii began to record 3 identical images for each exposure I took. These were not bracketed in any way, all shot in AF-S mode, just 3 identical files with the expected sequential filenames. The metadata for each is the same except for the filename. Any ideas about what's up with this? I'll check the camera again later today.

I bought my a7r5 before the compact models were available. I love my r5, but had the a7cr been available I would have bought it instead. 

Some sensor cleaning is done by an electronic action instead of mechanical action. My A1 is the same way. But the best way to answer your question is to check the sensor for dust and dirt.  Set the camera for the highest aperture you can, hopefully f/22. Take a photo of a plain white something, or clear blue sky, something light, bright, and monotone. Then view the image on a screen. Dust and dirt will be apparent. If it's there, perform a cleaning and check again. There is a point where in-camera can't handle certain things like smudges, so a good cleaning kit is required.