USB LUKS device is being mounted for non existent user after being prompted to unlock
When I plug in my usb which contains a luks encrypted partition gnome prompts me for a password to unlock the device. However, when the partition is mounted it is mounted for user 1001 (no such user exists on my system). The non encrypted partition is auto mounted for user 1000 (as expected). This occurs if I respond to the initial prompt, or I later mount it through nautilus or if I use gnome disks utility to unlock and then mount the partition.
I'm not sure what program is actually carrying out the auto mounting in gnome, but I figured disk utility was the most appropriate place to put this.
I have no custom settings in disk utility for this usb.
I noticed this change in behavior when I upgraded from Fedora 27 to 28, which pushed me up to GNOME 3.28. Previously the same usb would always be auto mounted for the user that unlocked it.
Also, I upgraded another computer from Fedora 27 to 28 and the same thing happened there. Except on this other computer user 1001 does exist, but previous user 1000 has been deleted, so on this computer the disk is mounted for user 1000 (rather than 1001 as expected for this other machine).