This is just an observation, but could also be considered a bug.
The pad is not connected to the filled zone (due to keepout), so it doesn’t really need thermal relief.
If there are several clearances, the max is always used (because each clearance is the minimum distance). If the thermal relief gap of the pad or zone is large enough it creates these two non-filled areas seen in the screenshot. KiCad also apparently tries to add thermal stubs but cuts them because of the keepout. I don’t think this should be considered as a bug, but it’s a matter of opinion what KiCad should try to do if it can’t connect with thermal reliefs. In my opinion it’s simple and logical that KiCad does what it can according to the rules and leave it at that. Trying to be more clever just adds possibilities for bugs and wrong guesses.
You can always change the pad/zone connection properties for that one pad and get exactly what you want.
It’s a good point that you can just set the pad to zone connection to ‘None’ in order to avoid the GND zone connecting to the pad. The thermal clearance of the zone is still in effect though, creating a larger clearance around the GND pad compared to the others.
What happens if you set the relief gap for that pad to some small value?
If the pad relief gap is set to the same value as the net clearance, it gets a clearance similar to the others.
I think I will stay away from doing that, though, because if the net clearance is later changed, they will be different again.
Maybe I’m missing something…
Can you explain why you do not want the GND pin to connect to the GND plane?
Edit:
From the post below: Wanting a “quiet” part of the GND zone is indeed a good reason for a construct like this.
(Did not want to add a full post for this).
I do, but not at that location - that part of the board is a “quiet” area where GND is only connected to connector shields and chassis.
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