Have you taken the door panel off to see what's going on at the latch? Could be a wire from the central lock or a speaker wire or something getting in the latch mechanism. Also, if you have the door panel off, get some white lithium grease or WD40 and shoot it into the mechanicals then work the handle until the grease / WD40 penetrates all of the internal areas. Check the linkage and the door unlock rod and make sure nothing is getting snagged. That would be the place to start. While you are there, you can lube the power window mechanicals and check your wiring to make sure nothing has worked loose (I would not sugggest using the white lithium grease for the window mechanicals- use regular grease for this). Not a huge deal to take off the door panel and check these things, just make sure you have some spare tabs as the WILL break. No matter, they are very cheap from the dealer. It won't cost more than $6-7 to replace all of the tabs while you're in there. Another point to consider is to reglue the map pockets, top rail, and side attachment panels while you have the door panels off. Reattaching everything in the panel will get rid of some annoying squeaks and rattles you might have and not realize until after they are fixed. I don't know how much you have worked on your car or if you have a manual. If you need a Bentley PDF manual let me know and I can get it to you. Good luck. My last suggestion: DO NOT TRY TO USE HOT GLUE if you are reattaching the pockets and fixing your panels. Use a 2 part epoxy that is specific to plastic. I have seen several "professional" videos posted that use hot glue. The hot glue is NOT strong enough and it will fall apart leaving you right back where you started
. If you use the epoxy, you will never have anything loose in the panels again. Want to know how I know this?? I hope all of this helps.