Comment # 1 on bug 1156270 from Dominique Leuenberger

That must be an error in systemd - the udev rule is correct and IMPORT{program}
must not be compared to a value, so == is wrong and the error misleading
(systemd seems to try to give new meaning to == though; but at least the fix
for this still lies in system)

systemd upstream issue: https://github.com/systemd/systemd/issues/14062

Assigning to the systemd maintainers