The former, dated July 23, 2011, clearly shows him practicing law in Seattle, whereupon the later, changed within the past week, excludes that relative information.
Chances are Avvo got his address from one of the jurisdictions where he's licensed. An attorney can be licensed in one jurisdiction and live in another.
Actually practicing law in a jurisdiction where one isn't licensed is dicier. However, the definition of "practicing law" can be slippery. Traditionally, an attorney licensed in any US jurisdiction can appear in any Federal court, or can work on federal matters such as patent (and perhaps FCC issues, I've never done FCC work and don't know what's common with that). To practice within a state or appear in state courts, the attorney would need to be licensed in that state, or be admitted
pro hac vice and appear together with a locally licensed attorney.
If an attorney is physically sitting in State X, talking on the phone to a client who's physically sitting in State Y, discussing a lawsuit to be filed in a state court in State Z . . . well, it's a mess. The safest thing would be for the attorney to be licensed in X, Y, and Z, though most people believe that being licensed in X and Z would be sufficient to protect the attorney from charges of practicing without a license, and just being licensed in X or Z is probably good enough, if the action to be filed in Z will be handled by locally licensed counsel.
Also, many states will allow an attorney who is licensed in some jurisdiction (DC is popular because their bar exam is comparatively easy and their yearly dues are comparatively low) to work in-house as corporate counsel in another jurisdiction, but the attorney cannot appear in court on behalf of the corporation, nor may they represent anyone other than the corporation.
In the modern world, where people do a lot of business electronically and the client and the attorney may never actually meet in person, it's not necessarily clear what the rules are. Historically, the definition of "the practice of law" which is forbidden to people not licensed in the jurisdiction has been left intentionally vague, and prosecutors/bar counsel use the vagueness to punish people they see as bad actors, and ignore people they see as virtuous. If you think that doesn't really sound like "law", well, I agree with you.
I don't know any of the Murcks, but my hunch is that the DC Murck is a family member of the WA Murck, who allowed the WA Murck to use his address (since WA Murck is licensed in DC) so that people on the Internet don't get all huffy about the WA address. From Google Maps, it looks like a residential address, so that's probably the guy's house, and it's perfectly possible he never even knew about/thought about Avvo, since they make pages for attorneys whether the attorneys want them or not. If the WA Murck is going to take on a public role in the Bitcoinica problem, he's probably not crazy about having his home address on the Internet.
It's pretty common for one attorney to share offices with another attorney who needs a local address to receive mail or meet with clients, since often clients prefer to be able to sit down with someone in an office close to them. I used to work with a guy who had 3 difference CA "offices" in different metropolitan areas, though he only paid rent for one of them - the other two were friends who had a reciprocal office-sharing agreement. This is unremarkable and not suspicious in the legal community.