Quick reply as SWMBO is giving me the look.
I dont use the hubitat driver I use a mix of cjcharles driver for the ones I don't need scenes and Robin Winbourne if I need scenes.
I'll give u a better reply later 
Cjcharles driver is available via HPM and Robin's driver is here
I haven't ever noticed the none liner dimming, but saying that I cant remember the last time I use the retractive switch for dimming as all mine auto dim with the outside lux.
I just had a play with dimming via switch and sill can't see it.
All mine are H2 550's and 3 years old Installed with a complete rewire, I have no popcorning on any of mine.
There is a slight delay between pressing the switch and them turning on but it's like 0.5 seconds at best.
