I am using Ubuntu Studio 22.04 and I have three partitions that are mounting automatically on bootup even though they are not included in fstab. One of these partitions is on the same physical HDD as my root partition, and the other two are each on a different physical HDD. These three partitions are being mounted to /media/username. The only online post I have found with a similar question was here: Disk Not Listed In fstab
The answer in that post suggests that poster's drive is being mounted by the udev system.
How can I check if this is the case? I had a look under /etc/udev/rules.d which has only 2 files: 10-wakeup.rules I added myself, and 70-snap.snapd.rules. I ran the unsnap script after installing this instance of Ubuntu Studio.
What else can I check to try and solve this issue?