Visible or not

My ex has a dog who is he believes Labrador and German shepherd Cross.

When my ex calls round for coffee a couple of times a week he tells us about the other dogs they have met on their walks. Gus is a very sociable dog and likes to play and run with the other dogs.

A few months ago he was telling us about the time a Dalmatian wanted to play but Gus just ignored him.

Today the same happened. We are beginning to think maybe Gus just doesn’t see the Dalmatian. (I don’t know if this was the same dog or a different one).

Could it be the broken pattern of his cost that makes him invisible to Gus?