Puffiness in canvas along plank seams


Novice Canoe Restorer
Just back with the 1929 OT from the lake. Hosed it out to get the mud/sand out using the soft shower setting on the garden hose. Now in the "rack" in the garage, I notice puffiness on looking at the outisde of the canvas. Obviously water that seeped past the planking seams on the inside of the canoe (along the tumblehome) wetted the canvas and caused this puffiness along the seam as viewed from the outside. I am guessing that it will abate as the canvas dries but it sure spooks me.

Any experience with this?
There is no need to panic. I have observed the same behavior with canoes that have been newly canvased, varnished, and painted. It was all gone the next day leaving no permanent damage.