You should be able to keep your preferences separate on a family account, so it shouldn't be a problem with that as far as I know. If we can't get this figured out with the cache, I'll escalate the post and see if a moderator or Rock Star can help us out here.
I have had this same issue with Repeat auto-enablifng itself and have narrowed the issue down to my car's bluetooth system. I drive a Ford Everest/Endeavour and every single time my phone/spotify connects to the in-vehicle entertainment system it enables repeat. It is HIGHLY annoying but I can't seem to find anyway to sort it out on Spotify or in the Ford entertainment system. Perhaps you have a vehicle that connects to spotify automatically too and it's causing it to enable Repeat like mine does?
I’ve been using a USB connection for some time, since before I created this report initially, so maybe. I only started using the Bluetooth connection in the last few weeks so that definitely isn’t it, but what I can say is that Spotify’s interface on the phone is different between when I use USB vs Bluetooth methods. With USB, it seems to just send audio like an AUX output; with Bluetooth, it looks like CarPlay.
It is your car (or possibly another Bluetooth device) that does it. In my car, VW2017, the settings button that shows while media is playing from the phone has a checkbox for “repeat/shuffle”. I unchecked that and now it doesn’t happen anymore!