Took me 4 hours to fix it, but after deleting the NavMeshVolume and also the RecastNavMesh, opened another level, reopen the first level, placing again the NavMeshVolume and the unwanted delay finally disappeared. I am 100% sure that in my case it was the problem. I tried other solutions like checking and unchecking the “Use Accelaration for paths” in the character movement component inside my NPC but it didn’t work even after restarting unreal editor.