I recently got this chip, but when I tried to put it inside an airtite, it did not fit. It was too small. It looks like the chip was shaved down to give it a square edge. I don't recall rectangle mold chips being smaller than 39mm.

Shown are side by side pic, on top of a regular 39mm chip, and what it looks like inside an airtite with foam ring (note the space).

Anyone seen this before? Comments??