I have experienced this very same problem. My solution was to take 0000 dry steel wool to the dry pan. This worked very well. I scrubbed it pretty good. I thought that the initial seasoning created, for reasons unbeknown to me, a situation that just simply repelled the oil.
As for when things stick. I have had luck with boiling water in the pan, letting it cool, and then scrubbing it off.
I hope this will help. I know that there are more solutions to your problem because "There is more than one way to skin a cat!"