Best answer by Airgetlam
It depends. If you set up the Sonos Ones as surrounds for the room that has the PLAYBAR, then no, there's no significant lag. However, if you set them up as a separate room, there can be at least a 70ms, delay for additional processing of the signal.
And that delay is only for anything being sent by the TV. If you're using the PLAYBASE to play music along with the Sonos Ones, they'd be in sync.
Not sure you care, but all of this has to do with the method of communication between the devices. If they're set up as surrounds, they're connected via a low latency 5Ghz connection, but if they're set up as another "room" in the Sonos software, then they communicate on a 2.4Ghz channel, which has greater distance capabilities, but is a slower processing speed.