Same thing has happened to me, Lee. This same sort of sloppy course layout is what caused the misplaced turn around at the 2019 Cherry Blossom 10 Miler, thereby disqualifying a couple of otherwise possible records. GPS coordinates for this turn around could have saved the bacon for this ill-fated race.
I have been doing this long enough that I have come back to courses I certified years ago to find that some of the "fixed objects" I used as reference points are just gone. In my latest incidence of this, I found the power company had torn down all the telephone poles on one street and replaced them with new ones in different spots. Thus, two mile marks I referenced to these poles were lost forever. Google Earth helped me find the approximate mile marks for the course layout team. The course needed revisions and re-certification anyway, so only one year's event was affected, fortunately.
GPS coordinates are not an omnibus solution. Even in an area that was open to satellite signals when we measured our course, tall buildings or other obstructions could come along in subsequent years and render those coordinates useless.
If someone asks why certifications expire in just 10 years, this is a big part of the answer. No reference point strategy is perfect.