Yes, this could be an initial symptom of Canine Cognitive Disorder, which is common in older dogs. It has a longer fancier name and if I think of it I will let you know by supplementing this. You can probably Google it. Might be Canine Cognitive Dysfunction Syndrome or something similar. My JRT developed it at age 16. There are a variety of symptoms, but this is one of them. It starts gradually and gets worse. It's kind of doggy Alzheimer's. The good news is that there is a medication available to treat it and it helped our dog make it to 17 1/2. The bad news is it's kind of pricey. It wasn't too bad for us because he was a small dog, but bigger dog bigger dosage. I can't remember the name of the med either (this was a couple of years ago), but it might start with the letter A and it takes at least three weeks for the med to get into their system and start helping. Good luck and PM me if you want more info about the symptoms my dog exhibited. As I type things are coming back to me. The name of the med might be Anipryl. He was on several meds at the end so I don't know if I'm confusing it with one of his other meds, but that one rings a bell.
Just Googled it. It is Canine Cognitive Dysfunction and it is Anipryl (or at least that's the brand name, not the generic name.) Good luck.