Dave,

I haven't seen your hive.  However, the bees hovering out front are probably no problem.  As the hive gets more populous, and on a strong nectar flow day, the returning foragers stack up before entering the hive much like airplanes at a busy airport.  As long as they don't feel like its consistently causing a traffic jam (and trigger swarming).

The restriction near/in the entrance, however, I'd clean out.  You'll want to make sure they're not building this additional comb because of running out of room (either by the follower board being too close, the brood chamber being honeybound, or the hive being just too full) which could trigger swarming.  You could move the follower board, add empty top bars checkerboarded in the brood chamber, or transplant a frame or two of brood to another hive to help alleviate the crowding.

That's my opinion.

Allen Engle