I was trying to find this post again and glad I found it. My right (passenger side) rear door had been stuck for a while since around mid May with the same symptoms as your OP: after using the handle, the window does go down and door moves slightly out, but can't open (also to close it properly, you must push it back in until the latch clicks). The service center that handled my case had parts on order preemptively (a door controller) since then and my appointment was continually delayed waiting for that part. I finally contacted through the app to see what was going on, and they had me come in, saying they had all the parts necessary.Solved by Mobile Tesla guy, who said he had never seen this problem before. The inside door panel had somehow scooted back a fraction of an inch so it was caught by the gasket on the door frame. Mobile guy adjusted the door panel in just a few minutes, and all is again well.
I had that happen once (door warning about it being open) when I pressed the door release on the door with the issue and didn't latch it back completely. You need to press the door all the way to make sure it latches completely.This post hasn't been updated in a while, but I'm having what appears to me the same issue. My passenger side rear door all of a sudden wouldn't open last weekend. I started walking away from the car, annoyed that my seven year old was taking so long to get out, but finally went back to discover him in tears because he couldn't get out. The door came loose from the latch and the window came down, but it wouldn't budge more than an inch - totally stuck. It felt like I could forcefully pry it open, but not without damaging something. I immediately made an service appointment. In the week wait up to the appointment, the door decided to open by itself on the freeway twice. Only the same inch before getting stuck, but I still got the warning chimes and had to pull off to force it back shut. My car is in service now, and they wanted $750 to make the repairs, as my 2018 Model 3 is no lounger under warranty. I complained and they admitted that it's becoming a frequent issue, but the manager said there was nothing they can do. After further inspection, they said they need to order the part and it will now only be $550, but I'll have to make another appointment. I consider this a manufacturing defect, and what ought to be a safety recall issue. I want to find out if there are more of us out there having these issues.