I had to restart Network Manager at some point and things started to work as expected when resuming from standby (suspend to RAM)...
I suggest people having the issue update their system and try again. Please post whether this fixes the issue or not.
On 23 December 2014 at 15:27, Tobias Bora <tobias.bora@gmail.com> wrote:

> https://bugs.kde.org/show_bug.cgi?id=339674
> Tobias Bora <tobias.bora@gmail.com> changed:
> What |Removed |Added
> ----------------------------------------------------------------------------
> CC| |tobias.bora@gmail.com
> --- Comment #12 from Tobias Bora <tobias.bora@gmail.com> ---
> I can confirm this very annoying bug, please try to solve it soon... I can make
> any tests you want to help you.
> --
> You are receiving this mail because:
> You are on the CC list for the bug.