I've had this cover for a long time and had never studied it closely before rediscovering it last night while searching for something else. (Great to shop in your own boxes!) It appears to be a legitimate bisect of Scott J80 postage due stamp:
The cover is an unsealed envelope postmarked December 23, no doubt a Christmas card, although there are no contents now.
The intent of the sender seems to be one of two possibilities:
1. Single piece 3rd class, which had been 1.5 cents since April 1925. Consistent with being unsealed.
2. A misunderstanding of the 1 and 2 cent local rates for non-carrier and carrier offices, respectively. Ashland, KY is a first class PO with city delivery, thus 2 cents would have been required, and the sender could have sealed the envelope.
Regardless of the sender's intent and Ashland using a dated dial in their Universal machine cancel, the nixie clerks in Ashland found it underpaid, examined it, and allowed it as a single-piece 3rd class item, but due. Half a cent postage due accounted for with half of a 1 cent J80 due stamp (beautifully tied!), and an uncancelled half cent Hale stamp at the lower left for change.
I did not happen to find any bisected due examples from Ashland after a cursory search of the literature.