After having big troubles with connection drops in two different hotels last week I switched between 4 different versions of the drivers of the card and none helped.
And then, by chance, I stumbled upon the following two hotfixes for Windows 7 (it's what I'm using) on the Microsoft website:
I installed both hotfixes, and all my Wifi-connection-problems with the AC 7260 were gone! I don't know which of those did the trick (especially as the hotfix rollup includes 90 different hotfixes), but I thought it would be worthwhile to share, and maybe helpful for other users. I guess it's something in the enterprise hotfix rollup, as that would make it totally reasonable why the engineers at Intel have so much trouble with fixing it - as they maybe can't reproduce it on their machines that might have the rollup targeted primarily for enterprises installed by default.
I'm curious it that's of help to others and what your experiences might be. (I for my part started looking for some more hotfixes and got an annoying issue with my notebooks hotkeys for brightness fixed that way :-) ... and I thought it was a problem of my computers bios - no, it was a Windows issue that could appear in some circumstances ...)
Thank you for the feedback. I am sure this will be helpful for other users.