After filling the water bottle from the pump I get 83% of it (or 5 del, which is important in this case). Canteen fills ok, to 100% (10 del).
The issue is that they are consumed by 2.5 del (25% of canteen, 41.5% of bottle) instead of 2 del per use (this way I get 2 and 4 uses from bottle and canteen respectively when I should be able to get 3 and 5) and that I'm not able to pour water between them.

100% reproducible on my current character, don't know if anyone else is experiencing this.
Vid is here, all issues demonstrated:
http://www.youtube.com/watch?v=-6SPm4I17Iw

EDIT:
This behaviour of this items is not fixed by taking another canteen\bottle, they all perform the same