It's not buggy in my experience; I've never had it trigger (or not trigger) unexpectedly. That being said it can be prone to user error as outlined above.
give it time, it will fail you too lol
here are a few instances not related to user error
1. software "dings" making tone confirming signal sent to garage but door doesn't open
2. software "dings" making tone confirming signal sent to garage but door doesn't close
3. manually triggering homelink button, door doesn't open
4. manually triggering homelink button, door doesn't close
5. homelink flat out forgets garage code and i need to have it relearn signal
6. summon disconnects or fails halfway through moving car, autoclose will initiate thus closing garage door on car that isn't fully cleared.
7. instances where two teslas are coming or going, homelink signal does not differentiate open or close commands, garage will open as first car approaches but then close as second car also approaches or if two cars are leaving, it will start to close but then reopen.
8. geofence distance varies even after you set it
that's fine if you're not having any issues, and i am jealous of you, but the vast majority of users will run into at least one of my scenarios. any fail is a fail nonetheless and cannot be trusted to work flawlessly. i forgot how that saying went, but it has something to do with no one trusting a calculator that is accurate 99.999% of the time but will occasionally give you a wrong calculation.
We also back into our garage but have set homelink to only work with manual triggering and this has solved all the issues we had with the automatic signaling. Yes it's an extra step, but it's deliberate and we are still in control of it's operation. Because we can't trust it to close automatically when leaving, we used to look back and visually verify that it closes all the way. Since we have to double check anyways, pressing the button takes no extra time and we can do it right after we clear the door rather than waiting till we are halfway down the street just to hear it "ding" and nothing happens.