Not really because I don't read the manga first but I do have several examples:
Love Hina
Manga 16 volumes (I think) in the end
- Spoiler:
Keitaro and Naru get married
but in the anime even after Keitaro's sister gives up on him the series dosen't really finish.
Same goes for Negima first season ends before volume 8 of the original. Inuyasha they are now making a new season, and In fma it went totally off the rials I am sure because in the manga I don't think they go to our world, but now brother hood is out and it is completely different.