As several users have stated, LG webOS 2015 TVs experience bad audio quality in the already lame Spotify app.
"At first it seems to sound fine, however from time to time it jumps a fraction of a second producing odd tempo shifts. It only happens with Spotify app. Tried several receivers with ARC and optical, same thing." 2015 LG UF7700 tv
"Skips slightly probably every 40s or more frequent. Setup details: Analog audio output, Spotify v1.0.7, webos 2.0.2-454401, tv model; uf772v with firmware 03.03.57 "