Sometimes when I want to take a weapon lying on the ground something odd happens.
For example: I throw away my pistol to get a Ruger from the ground and the soldier throws the Ruger at the same second as I take it. It's really annoying and happened to me several times. This wastes much time and I get killed before taking hat weapon.
Oh, and it's not that I'm still holding the "thrw away" button- i checked.

Has anyone had this problem?

This happens because you grab the weapon before your "throw weapon" animation has finished. Just wait a moment longer before snatching that weapon. Besides, you have to reload the weapon as soon as you grab it anyway, so it's the same either way.