OnTriggerenter: Not working when both objects are not moving/at rest?

In my games I am trying to make it so that when a character touches a health pack or some other pickup, he will pick it up.

I want to do this with colliders, but it seems that OnTriggerEnter only works when at least one of the colliders is moving.

This is a problem in my games where a character will be standing still on the place where a health pack will respawn; then it respawns, but he doesn't pick it up unless he moves again.

Another example of this problem is when a character is using an area-of-effect healing ability; I want it to work even if the healer and healed players are standing still.

Is there any way around this using colliders?