So, Am I the only one with this problem?

It would seem so.

Ho thats not good.
Someone know what might be the problem?

Try verifying the game cache and removing any mods you have. You should also upload DxDiag or something.

I cannot reproduce this, switches to full-auto after pressing "Next weapon" once.

Thanks guys, will check what you said AD2001,
hope to fix this, it's annoying :(

OK, so my bad, i have two profiles and my keys got mixed up
and i had the "next weapon" key mapped to "change gunner weapon"
for some reason also.

Strangely only the Zafir didn't manage to switch firing modes
all the rest of the weapons worked OK.

Anyway, this can be closed, sorry :|