With the slide off is there pretty good spring pressure keeping the lever down. Not slop or take up then.
Wonder why they would say that isn't the problem. It's very easy to hit the lever with the thumb but with multiple shooters having the same issue thats not likely the culprit.
You've done the slide off, install slide stop, insert full magazine inspection to make sure the bullets are hitting the lever?
In Memory of Paul "Dietrich" Stines.
Dad: Say something nice to your cousin Shirley
Dietrich: For a fat girl you sure don't sweat much.
Cue sound of Head slap.
RIP Muggsy & TMan
"If you are a warrior legally authorized to carry a weapon and you step outside without that weapon, then you become a sheep, pretending that JOCKO will not come today."