In our last game, the heroes (i forget how) put a bleed on a Stormtrooper.

The card says until the action of removing the bleed is taken, the target takes 1 strain?

How does this effect 'units' that dont have bleed? I understand if it is applied to a hero.

Anytime you're supposed to inflict strain on a unit that can't suffer strain (e.g. imperial units, rebel allies) that unit suffers one damage instead. So if I stormtrooper has the bleed condition, every time it takes an action other than removing the bleed it takes one point of damage.

Non-heroes do not have Endurance. When a non-hero would suffer strain, the figure suffers damage instead (preventable in skirmish by discarding a command card from the top of your deck).

Non-heroes cannot recover strain. Recovering strain does not do anything, only when heroes recover strain they recover damage for each strain they cannot recover.