Forgot to mention another thing. Mine does not work if I plug the USB cord into a USB hub. It only works if I plug the cord into one of the USB ports on my computer itself (an iMac). This surprises me because I think there's a hub built into the computer itself, which is how the computer has multiple USB ports in the first place. I think it was somebody here that suggested I try that -- sorry I don't remember who!

On another forum someone suggested spraying some electrical contact cleaner into the wheel but the Fuji tech said that could risk frying the rest of the cameras electrical so I haven't tried that.

I have an x100VI with 1.01 firmware - did a reset already and didnt solve issue I am about to describe. Can you all see if your camera does this: Switch to C mode, step down to f16 and then press shutter half way. Does your screen go dark? I have tried playing will all settings (have had the following so quite familiar with the menus: x100, x100f, XT-2, X-Pro 2, XT-3) , only happens in C mode. If you find this can you report to Fuji @ digitalinfo@fujifilm.com. They told me they had not seen this before and that it was normal behavior because the shutter is closing, but the shutter closes in S mode as well.

That’s a common problem with many cameras, filters irritating the autofocus.

I can't vouch for the Sigma on the X-S20 but I do have a Viltrox (27mm f/1.2) and the startup speed is identical to when I have the Fuji 18-55 on it.