I think cranking the bottle real tight will get the seal fixed. That or normal ware from putting the cap on will break in the threads to eventually seal good.
I hope this helps. I filled the bottle with hot water and then submerged the bottle in a pan of hot water. With the bottle in the hot water I folded the tube over and did the squeeze several times. Before I did this I had a little seep but after this I didn't. It worked for me but who knows if it was the process or just the normal ware you spoke of.
Rob, you and your team have outdone yourself with this one! I'm a hard-core, exclusive Reo lover and I could never imagine that they could improve any more. Holy Toledo, these P-67's hit like a truck! Wowser!