Synchronisation iTunes copies movie again and again to iPhone

Hello,

synchonising my MBPs iTunes Library to iPhone, since a few days one spec. movie is copied again an again!

All went well but this single one is synchronised every time, even, when the last copy was succ. and the movie is definitely local to the iphone and not marked as cloud-entry.

Are there an ideas, what to do, because it needs a lot of time every synchonisation, to copy.

greetings

A.