I have the same issue on my 18, clean off with vinegar around the rim before putting it away.
Pork butts then cause the black sticky mess which can require some force to remove the lid.
Tried an empty cook & no binding issues.
Interesting Gary, or I somehow managed to misfit mine!? Not sure how, or maybe I had a larger hover vs my smokenator.
Sold now, so no chance to find out! Shame if it does as looking to expand capacity :mad:
If its the hover grill from a 22.5 kettle smokenator, then no.
I was hoping likewise but was too large so sold it alongside the smokenator when I got my WSM 18.5