Is this a 22? I am surprised (and not surprised) that Weber still has not addressed this. It existed even in the prototype stages and has bothered the dickens out of me since Day One.
The original 18's tooling for the door was created by a master model maker using renwood or actual wood. A few doors were stamped out and the fit was checked. Good seal? No? Then they'd sand a little more and shape the forms until it worked properly. The final result was an 18.5" door radius at the bottom and when the spring action of the door (to hold on the door) was latched at the top -that radius is the same as the bottom with gradual loading along the side edges. Quite a bit of brilliant engineering led by Eric Schlosser.
The "tough" part is that the radius at the bottom of the door is essentially 18.5" At the top it's a little different radius and they do not share the same center line. It's off set a bit. But what happens as the latch is drawn in as you close the door, the door flattens out and does not butterfly or show gaps. Not to mention heat expansion! So there is a lot happening to get that to seal nicely.
When the 22 was being developed, they refuse the long process of having a model maker properly assist in getting the right door fit (as there were none no longer employed at Weber). I calculated rough numbers to get them started on stamping Something, but they only tried adjusting the amount of pressure of the stamp/die used to form it -which.... That wasn't going to change a thing. Doing the same thing and expecting a different result?
Eventually they settled on some dimension numbers to produce the doors but I was never happy with it. You'd think after 10 years something would have been done.
I'm sorry you're having trouble with the seal of the door. Reshaping may help, but go slowly and a little goes a long way. Be careful not to cause that kink at the lock which causes the butterfly effect. If you have a large circular object to form it on as you shape it, that may help.
I believe there are some aftermarket doors that work well, but nothing like spending more money on something that already cost a lot -just to get it to work as it should.