Weird Plumbing Issue

[J Scott]

Any plumbing experts want to take a stab at this issue and see if you can provide a diagnosis?

House is a new construction built about a year ago.  It's on public water and sewer.

One of the sinks has an occasional sulfur (rotten egg) smell to the water.  Typically happens after the sink hasn't been turned on for at least 24 hours and typically only lasts for about 5 seconds after the sink is turned on.  But, it's a relatively strong smell, and it only comes from that sink.  

That sink is attached in-line with another sink and a tub (it's between the other two fixtures), and those other two fixtures don't seem to have the issue.  Makes me think it's not a supply or supply-line issue, but I'm certainly not a plumbing expert.

Any thoughts?