1. Pick Lone Druid and level up and summon the spirit bear
2. Give the spirit bear any order
3. While the bear executes the order, level up Summon Spirit Bear

Result: Leveling up the spell causes the bear to forget its order and stand still, doing nothing until the order is given again. Also, the death animation of the previous level bear plays.

Expected: Leveling up does not cancel the bear's current orders and the animation should probably not play either.

Reason: As of now, when leveling the spell, the current level bear simply gets killed and replaced by the new level one, causing these inconvenient interaction. This also causes its cooldowns to get reset.

Dream solution: In my opinion, it would be best to use a modifier on the spirit bear to update it to the new level, instead of killing the bear and replacing it with a new one. The modifier would increase hp, hp regen, attack damage, movement speed, armor and model size and reduce base attack time. As for the bear's abilities, give the bear all the abilities from level 1, but keep them inactive and make that leveling up Summon Spirit Bear activates them one by one.