I have noticed some similar behavior on my 2016. It refuses to play the first song when you do a search, it will start with the second song. Also, when you turn off the ignition then start the car up again it will continue the last song played but will not retain the search, it just plays the next song in line from the entire library.
Thirdly I have noticed that after a song is completed, before the next song starts it will often play a second or two of a random song, occasionally I will recognize the snippet but usually it isn't long enough.
I don't know if it is an iPod issue (mine is pretty ancient) or a Sync problem.