Just got a HT-XT3, and there is a slight delay in audio. Not much, actuallt I might not have noticed right away if I wasn't looking for flaws.

I use optical toslink from my tv.I love the sound, but thisbugs me. The audio is delayed, even if I have of course set the in-built lips sync to 0ms. Adjustingit up makes it worse. I first noticed when running the tv speakers and the ht-xt3 at the same time, I heard this echo effect. I have had two other soundbases here for testing, and they have been totally in line with the inbuilt TV-speakers (both soundbases connected via optical)

When I run a youtube- test like this one: https://www.youtube.com/watch?v=szoOsG9137U - the inbuilt TV speakers are totally on the spot, but there is a noticable delay with the HT-XT3. 

I have updated the XT3 to the latest firmware. I use the toslink connection. It is the same with all sources (PS4, BlueRay and my digital cable TV-box)