[LUX3]

My 2016 F30 330i has done 28000km since new.
In my ownership over the last year I have driven 6000km, regularly checking the coolant level .
So I'm adding about a cup per 1000km. That's around 2 litres over the year.
There is no visible leaks or sweet smell of hot coolant.
Have tried 2 new caps on the coolant reservoir.
Checked the level about an hour after driving while still hot and there's plenty of pressure so I'm sure it's pressure tight with both caps . No evidence of dried coolant residue around the top of reservoir.
Also loosened the reservoir bleed screw and no air bubbles evident so not a bleeding problem.

So where's the coolant going?
Anyone else have this problem?
What's the fix???