I was hoping the IL's didn't have this problem, but I know what you speak of exactly. my KI1 joysticks, I recycled the actuators from the original ones (they were the white kind, which I'm guessing were like old style IL's, not the Happ kind) and those perform like a dream.
then when I got my KI2, the original joysticks were terrible. they were derivative of the Happ Ultimate design, had these extremely bullshit stiff springs on them (which is weird, usually the Ultimates are too floaty), and overall just performed horribly. so I thought I'd try and repeat the magic and well, the set that I wound up getting for KI2 did what you speak of, 1 was good, 1 was bad.
I did it kind of the dickhead way, I sanded the bad stick repeatedly until the actuator stopped turning with the stick. it worked fine in the end, but I'm kind of wondering if it would make any difference if you doused it in 3-in-1 oil... lol
you could potentially jam the stick in a drill and use some steel wool on it, kind of like how people remove rust off their Wico leaf sticks... I'm sure that would work effectively to correct the problem.
obviously it's a manufacturing process thing. and apparently it doesn't mean shit if it's a Happ Competition or the IL kind.
IL Eurostick right?