There are a lot of pieces on the board at the moment for the bond market rally that's been intact since mid-March.  That rally began with a friendlier-than-expected set of Fed rate hike forecasts, but the baton was quickly passed to political drama and geopolitical concerns (healthcare bill, Syria, North Korea, French election, British general election, etc).

Over the past few days, we've seen the US-related issues fade to the background while European issues have taken the spotlight.  Yesterday it was British PM May's call for an accelerated general election that hurt EU stocks and helped bonds.  Today it was a partial rethink of yesterday's gut reaction combined with several other factors (increased supply, strong data, French election forecasts) that pushed European markets back in the other direction.

The European bounce came at the right time for US bond market technicals.  Yields had just hit "the gap" between 2.15 and 2.17% created on the way up in November.  Markets love to fill gaps.  The first visit tends to be a bounce, and there were no objections to that game-plan, given the European momentum overnight (toward higher bond yields and stock prices).  

In fact, Treasuries weakened almost exclusively during European bond market trading hours and leveled off immediately upon the European close.  But don't take my word for it:

Interestingly enough, the bigger-picture implications were discussed in The Day Ahead, as well as the daily Huddle/video available to MBS Live subscribers.