This most likely happened due to the game update (reboot). Sometimes that can mess with the Voice of Seren, as you can see from the tracker here: https://twitter.com/JagexClock/status/1229359946212487169?s=20 It was Trah hour just before reebot (or as soon as it hit) at 11am.

So nothing to worry about, it should correct itself soon, but if it persists way longer than expected then we'll look in to it :)