This sounds much like Richard Hess’ definition of “blocking”. I’ve usually seen this on nearly every reel of Scotch 201 or 202 tape (both have no back coating). In those cases, there is no fix except a stupidly slow wind. Occasionally, even that can render the tape unplayable near the head. But I have noticed it on some batches of 456 as well, less adhesive but more flaking. You can see through to the back coating on the oxide side of the tape.
He’s done experiments with freezing tapes or cold temperature playback in addition to relubrication, so those may be avenues to check out.