Ooff, lots of scary possibilities in that article.Al, this is a long article & they spend a lot of time reiterating that you should go to the vet, but it lists some of his symptoms as possible cognitive disfunction. it might be interesting to know if he has some of the other symptoms as well.
https://www.aspca.org/pet-care/dog-care/common-dog-behavior-issues/behavior-problems-older-dogs
Luckily I don't think he is having any other symptoms, but I will try to keep a more careful eye on him over the next week.... see if other things are happening.
And he does go in for his yearly vet checkups. I just don't think she is a good vet.
Might consider taking a road trip to a better vet.... after a week of more intense observation.