I just tried reproducing this with the most recent from the link above (v4.3-rc6-unstable) and couldn't, then went back to the current wily kernel (4.2.0-16-generic) and still can't reproduce it.
So now I am wondering if the updated firmware for the BCM43602 wifi card in linux-firmware 1.149 fixed the underlying cause?
I'll see if the problem reappears over the next few days and if not, will try reverting linux-firmware to 1.148 to see if the problem comes back.
I just tried reproducing this with the most recent from the link above (v4.3-rc6-unstable) and couldn't, then went back to the current wily kernel (4.2.0-16-generic) and still can't reproduce it.
So now I am wondering if the updated firmware for the BCM43602 wifi card in linux-firmware 1.149 fixed the underlying cause?
I'll see if the problem reappears over the next few days and if not, will try reverting linux-firmware to 1.148 to see if the problem comes back.