When I summon a lightwell, I can use it fine once. But after that, it won't give me the buff again until I leave combat and re-enter combat.
I only had lightwell work properly 1 time since I've got it and I've used it easily over 50 times.
Yes, I had Lightwell ability, I spawned it, I was able to click on it once while fighting, it gave me the normal healing, then I wasn't able to click on it.