Hi. First, the Group Audio Delay referred to in the Sonos response is not relevant to your problem so please don't be distracted by that.
As implied by Danny, it's not really clear in what order your devices are connected. I am going to assume that your audio is bypassing the TV, because that is the point of Arcana. If I am mistaken then we'll think again.
Now,, the audio sync problem that Sonos users have usually had has been audio lagging picture because the TV outputs the audio with a lag. But I am wondering if you actually have picture lagging audio, because that is what I sometimes get using Arcana. I think it is caused by video processing in the TV post-Arcana.
You can use the TV Dialog Sync setting to improve / cure this.
Could that be your issue?