My home field was 3SG forever... It has had a published NDB instrument
approach with the identifier being HYX, for decades... Turns out that
the FAA failed to change the field identifier to HYX at the time of the
ndb installation... So very belatedly a couple of years back they
finally changed the field to HYX... Now we have an ILS installed and
ready to be turned on and the FAA now says the identifier will be
changed again to HQY... I refuse to spend money on new charts until
they actually do it because the odds are it will change before they
actually publish the new identifier... (mutter, mumble)

Denny