Auto iso in video keeps changing iso, ruining the footage. Camera was on a tripod in a church when people hardly moved and with constant light, but the video was getting lighter and darker. I noticed it during outside too when did some video outdoor too. Any option rather than put it to say iso 160 as outdoor when sunny and cloudy you would need auto iso to compensate when the sun goes behind the clouds.
I am importing from X100V on a High Sierra iMac with no problems.
Are you using Image Capture to import? If so have you checked the destination selection at the bottom left f the window? Make sure you explicitly specify a non-ambiguous folder name (e.g. not documents) so you can be sure of where you're looking afterwards. Also you could use Search to search for a specific filename that you believe you have downloaded.