Yes, I had the same issue on the newer ones. If you connect to the box though ssh and run `top` you most probably would see a process called brcmpatch using 100% of one of the cores. To get rid of the issue I had to do a reset config in LE settings. a reboot after that, it was all fine. You will lose all your settings though including any kodi addons that you may have installed.
Thanks very much for the reply.
Didn't work for my box, maybe time to finally bin my M8 and get a second s905 or s912 box.