Seconds... as it is a BT test... where is the latency test? In general bluetooth audio and video is a bad idea in the main core of the buffering protocol.
I have a Sonos Connect and Bridge. Connect goes into my PS Audio Sprout Coax/DAC, and then to Paradigm speakers. The Sprout also does Bluetooth. I have used the Bluetooth and it works flawlessly. But my main sources of music are vinyl from my Rega RP3 TT and FLAC streaming from Deezer through the Sonos.
I have had the Sonos since 2011 and it is a brilliant device.