Looks like I might be swapping frames for one that needs a slightly shorter post. Even if I don't end up with the issue, it wont do me any harm anyway.
My post is the current version, bought 2012, black collar, proper barb/connector setup, etc. It's a right-hand lever (so under on the left) 125mm drop and 420mm long.
Anyone interested in a swap for a 380mm?