For a while it's been quite difficult to open and close the trunk on my Roadster. I commonly would have to hit the trunk release button multiple times, and it got to the point that the only way I could get it to open sometimes was to sit on the trunk lid over the left hand latch.
I had the Tesla Rangers look at it when it was in for its 24,000 mile service, and the problem turned out to be simple. The little adjustable spacers forward of the trunk latch (the ones that land in the indentations on the main part of the car) had gotten out of adjustement. They were set too long, and so when the trunk closed it was pushing hard against the top of the latches. This pressure is what caused the latches to stick, and is also why sitting on the trunk lid helped.
Fixing the problem was as easy as reseting the spacers.
I'm posting this in case anyone else is having the same problem. Once you know what's causing it, it's an easy home fix.