Expansion/Control joints in masonry wall

Can someone explain why any mason would fill control joints with mortar?
Did a commercial inspection of a 20 year old post office…buiding was comprised of a double wythe masonry walls, 12" block and 4" brick veneer.

They tooled the joint to make it appear to be an expansion joint, but it appears to be mortar…doesn’t make any sense to me?
It’s as hard as a rock…could it be a sealant that has just hardened?

Joints occur at every window…about every 20’ or so around the entire building.

Cohen 016.jpg

Cohen 017.jpg

Hey Kevin, with out seeing it “live” I would have to say it is sealant that has aged, quite common. Still “gives” without letting moisture in.

It looks like sealant to me too, but it could be either. As long as the horizontal rebar is not continuous through the joint, it will still allow for movement. . .

Just readhing here, but could those continuous lines be a part of the elevation look? Architects do staranger things…