Spencer

Mine does that too. My guess is that it's the IBIS unit which is controlled with magnets. When the camera is on the mechanism is active, IBIS does its job and there is no clunking sound.

I've just been playing around with raw files of the Fuji X-S10, using Hex Fiend on macOS. If you replace the instances of X-S10 with X-T30, then Capture One will open those files. You could also replace X-S10 with X-T3 but then you have fiddle a bit because that's one character less and the following bytes will move one position forward. Warning #1: only do this if you know what you're doing. Make a backup of your raw files first before you start editing them!! Warning #2: I don't know if the result in Capture One is the same as proper support in C1 v21.