Jasper did blow out a puppy coat, probably around 4 or 5 months, so that's probably what Baxter was doing. What grew in was slightly less soft (except, oddly, on his face and ears) and a little denser. I wouldn't worry about it unless he started developing bald patches, was really itchy, had hot spots, etc. etc., as that might signal a different problem. Jasper also has a constant shed cycle--that is, he loses a little hair, but all the time. This is common among pets that live indoors, and I've been told, Vizslas in general (probably because they're pretty much always been in-the-home pets?).
You'll just want to keep an eye on the quality of the coat in general, as born36 said. Regularly brushing the dead hair off may help reduce the amount that's left all over your home, if that becomes an issue, plus it helps distribute coat oils evenly.