We got our doubles stuck rapping off the oak on the top of P2 of overhanging layback. While we were trying to get them loose someone came by and said he has seen at least 3 groups get their rope stuck there.
We used another rope and went up Something interesting (nicer route) to get to the top and rapped back down to retrieve the ropes. The knot gets stuck in a notch just over the lip, a good 15 feet from the tree.
I was going to cut the slings but the only other trees were small pines.
If you do OL its better to go to the top and rap down 3 pines. The last pitch is junk but better than wasting 2 hours trying to retrieve your ropes.

what knot did you use to connect your ropes,?

Probably doesn't matter, sometimes you just have to figure out how to avoid the crack.