From what I have observed the Pack Leader node does not proc when you have the Pack Hunters node from your wolf summon, my wolves nor the sabertooth ever jumped when I had Pack Hunters active. Aside from that the sabertooth seems to occasionally leap to what I am assuming is a far off enemy instead of nearby to where I land and it appears they do not jump unless they are already engaged in combat/ an enemy is attacking nearby.
Also on a smaller note there is no icon indicating that the buff from Warrior’s Entrance Node is active, In the character sheet you can see the bonus damage in your stats so it does seem to work there is just no indicator.