Regarding the cap, this can be caused by the inner cap.
It is also a minor thing it is not necessarily a wrong cap.
You could also try to fix it easily when your cap is an older one which still has the screw in it to unscrew the cap top / clip.
Just take it apart and take a look what the problem might be.
No big deal.
My 146 cap makes 1 turn.
You could be right, here.
If it is a ill fitted inner cap, it could be fouling the nib tip, preventing the cap from closing fully (the half a turn issue), and could also be causing your clicking nib issue by twisting/fouling the nib tip as you cap it?
Dunno. Just guessing. But, it's worth a look.
Had a similar issue with mine (as I mentioned above) which twisted the tines out.
Pterodactylus has one turn. That's fine.
Mine has about one and a half turns. that's fine.
But I don't think half a turn is enough.
(Cue: flood of posts on "the merits of my half a turn 146 cap" etc)