I don't remember how old Dakota is, and it probably doesn't matter. The only dog I've seen doing this was one we had when I was a child. The vet said she was having seizures and she was treated with phenobarbital. Maybe if your phone will take a video, if these spells continue and you can capture one or more on a video, if you do end up at the vet you'll have something to show him/her so they can see what you're seeing.
Sorry you're having to deal with things with both dogs at the same time, as if one isn't stressful enough!