I have RouterBOARD 962UiGS-5HacT2HnT
setup is simple:
Internet came from wi-fi on AC and shared with N wi-fi and LAN. all works fine, except one - connection to AC wi-fi periodically (after an hour or couple hours) lost. to restore it's enough to change AC Interface channel width from 20/40/80 MHz Ceee to 20/40/80 MHz eCee (eeCe) or other value or change band from 5GHz-A/N/AC to 5GHz-only-AC (or back) and push [Apply] button. after a few seconds connection restores and Internet works again
I think that configuration is ok, because sometimes all works 24+ hours without my pseudo-reconfiguring
firmware is latest stable, but same problems was with every firmware
may be I can run some script, that restarts AC radio id connection lost (ping to AC wi-fi ISP lost)?