Artwork and music out of sync using iPhone 7 in BMW

Whether I use Apple car play (wifi) or BMW iDrive (bluetooth) the music and artwork quickly go out of sync. With Apple car play it does seem to synchronise eventually but via bluetooth the artwork always reverts to the same album I first played days/weeks ago and never synchronises unless I skip forward and back a few times - not advisable whilst driving! Is there an easy way to solve this problem or is it just an unfixable bug