Ok so it seems that the new unreal version doesn’t work if you don’t enable the Use acceleration for paths option.
Previous editor versions worked fine without that option enabled
There is no need to change the default animations blueprint (those for manny or quinn)
only enable that option in the ai character blueprint.
thank you for the answer, that bug was infuriating
Yeah acceleration isn’t updated unless the option is checked.
I had to change my animation class since my npc blueprint doesn’t yet share the same parent as player blueprint but you might’ve had a different approach.
I’ve had the default third person shooter with the two mannequins. Using that setup out of the box all works if one enables that option.
I’ve verified for past unreal versions and it worked fine without that option enabled.
I don’t know the systems, just learning now 
so don’t know what changed why now it needs this.
Thank you. Enabling “Use acceleration for paths” worked for me!
This actually solved my issue
Youtube video from LeafBranchGames Channel
He help us to solved the problem with this video :
