Personally, I keep my foot firmly on the brake while stopped. No need for "hill assist". Don't dven need it on my manual transmission cars cause I know how to drive. Lol
It has been discussed before as being "completely normal", even by my dealer. You can take it in and have them "flash" the transmission module. That has not seemed to help though. Welcome to the forum.
I replaced all mine with regular LED's (read: non-canbus) and they work just fine. Not sure what your problem could be. Take them out and reseat maybe?
Is it this one?
http://www.ebay.com/itm/New-Engine-Splash-Shield-Front-Dodge-Journey-2009-2010-CH1091102-5116301AC-/350668503337?fits=Make%3ADodge%7CModel%3AJourney&hash=item51a578b929:g:Z-sAAOSwepZXRS2t&vxp=mtr
Check a caravan forum. This forum is for Dodge Journeys. But maybe try a different "mechanic". That's such an old school term for technicians that actually know what they are doing.