Unbond the One SLs from the Playbar and unplug the Playbar and One SLs from power for a couple of minutes. Plug the speakers back in and add the One SLs to the Playbar as surrounds again.

You don't say where you live or what the source is.  Personally, I have experienced this issue in the UK with Sky Q recordings. My surrounds are sometimes 1 second out of step. To fix I stop the play back and rewind for 1sec and when I play, it is back in sync.

After sending a diagnostic report in, you should call Sonos Support directly to discuss it.

When you speak directly to the phone folks, they have tools at their disposal that will allow them to give you advice specific to your Sonos system and network.

Both suggestions above are good, if you’re unwilling to contact Sonos directly, but it ultimately depends on exactly why the delay is occurring. Those suggestion focus on different potential issues with the same symptom.