I just played the Flume House Party playlist under the Party category and it seems to be doing some weird cross fading stuff... The first song plays fine but when it goes to the next song it is still playing the previous song for a good 10 seconds or so until that song ends.
Sometimes when you skip a song in that playlist it also starts the next song at an arbitrary time in space that doesn't quite make sense... Not sure what is happening here but I have only been able to produce this issue with this playlist.
I have also been able to reproduce this issue on iOS, and it also only happens with this specific playlist. And the only way to fix it is by pressing the previous button that takes the scrubber back to the beginning of the song.
Background info: Windows 10
Spotify version: 126.96.36.199.gd8e05b1f