SC2Mapster

Just use the final effect then and give it a set duration.

Forget the period set that to default. Are you talking about buff 1 or 2?

http://www.sc2mapster.com/wiki/galaxy/data/behaviors/buff/

You will notice the Combat - Damage Response - Location field determines if the damage response trigger when the unit is attacked or does the attack. Another fault could be the Unit - Unit - Value field of the Apply Behavior effect being set to caster and not target.

In short your levelable Behavior ability applies buff A (for that level) that has a damage response on attacker that applies buff B (for that level) to the target.

Use a levelable Behavior ability that applies several levels of buff with a damage response on attacker that does the whole deal.