Found in Version:
Fixed for Version:
Nalenteris Brendu will ignore the ogrim (not attack it) if he is to far away from the player, when the player walks/runs up to the ogrim. This can easily happen when one has a character that is faster than most NPCs.
This can be solved by staying close to Nalenteris Brendu or by attacking the ogrim onself which will anger Nalenteris Brendu, but which can apprently still end well if one talks with his father (according to the uesp.net page).