Is this the ram issue?

ON Verizon and my phone has been randomly rebooting during a call if i try to open internet or some other app. Has also just randomly rebooted while navigating through the phone. Anyone else seeing random reboots and is this the ram management issue?

Wondering if i should just return it and pre order the 6s and try apple again as today's the last day to return..i don't want a phone that just randomly acts up..this is irritating.