As you may remember, some keys (BUS, SYSFS) that have been deprecated
from udev for some years, were finally removed in the last udev
For those who still had rules with the deprecated keys this caused
more trouble than first anticipated (there should be none in our
repos, but there could be leftover pacakges/rules). Essentially,
permissions were seemingly randomly assigned to nodes unrelated to the
broken rules (you could have rules that used to match on only certain
nodes now matching on everything).
The situation should be somewhat better in the next udev release, but
I believe it can never be fixed completely.
To sum up: if you are noticing weird permissions on your nodes, or if
a user is asking advice with such a problem, first check that no
deprecated keys are being used in any of the udev rules.