Possible but not probable. What make and model it it? ( not the chipset, just who made it and what mdel do they calll it)
Is the router plugged into a UPS?
Your router has as a very narrow window of temperture and humidity. Is it in a climate controlled enviroment?
My 'guess' is a brown out. Do you have an old digital clock you could leave there to check because a brown out is likley to reset a cheap clock; but this is all a moot point if the router is on a UPS.