gpsd udev devices includes a common USB Serial adapter. Collisions occur.
The following USB device has been erroneously added to gpsd udev rules file... twice.
ATTRS{idVendor}=="067b", ATTRS{idProduct}=="2303"
There is a comment about this Prolific Technology, Inc. device at the top of the Debian version of the file matching too many other (non-GPS) devices. But, it now exists in the gpsd version twice, the second time is for a u-blox 8 receiver.
In my case this chipset is also used in an astrophotography mount (SkyWatcher EQ6-R Pro). This udev rule causes gpsd to erroneously connect to a telescope rig... and prevents other software from using it. The root cause was completely non-obvious to the end user.
An Ubuntu bug was logged, but the suggestion was to make "upstream" aware of this issue as it appears downstream distributions (both Debian and Ubuntu) are needing to work around it because of how "prolific" this chipset is in other devices. I have two different astronomy devices that use it, neither are gps receivers.
Ubuntu Bug: https://bugs.launchpad.net/ubuntu/+source/gpsd/+bug/2012207