[tor-relays] tor-arm bandwidth state file -xxxx seconds is missing?

Found this error when checking my relay today: ARM_NOTICE Read the last day of bandwidth history from the state file (-xxxx seconds is missing) Every time I start arm, the -xxx seconds missing is different. The bandwidth graph is also stuck, but real-time data is still shown. Is this a problem with Tor, or with Arm? Anyone know a fix?