[photogem]

If you have the battery-door open, the springloaded latch should be right before the inner side of the WR sealing.
When moved (as if one wants to open the door), it should retreat well inside, giving enough space so that the door opens with ease.
When you close the door without moving the lever, it should close very easely with a clack-sound, i.e. the latch moves back and locks.

If this is not the case, I would send it in for warranty repair, because most likely something is then either misaligned or a faulty part.
I would not take the risk until that door goes further wrong!

[ShutterPro]

My door gives a little jump, and then I use my nail to open it completely. So no problem, I guess.

[Not a Number]

The door is after all weather sealed. It's not going to open until the seal breaks and the air pressure can equalize between the inside and outside.

[jeallen01]

On my 2 yr old K-70, I just slide it firmly backwards and then it pops open (rather quickly!) due to the spring.