I don't know how many manufacturers are involved in producing beehive springs. I know that I've seen 3 different brands break including factory production 88" - 103"
IMO, I don't feel that the Screamin Eagle dual springs have too much pressure on the seat or at max lift if set up properly. They seem to be set up properly when used by the MoCo on production bikes. Some of the MoCo optional (catalog) beehive springs DO have too much tension. They don't find their way on production bikes. I have checked their stage 4 beehives ( with 40,000 miles), and find them to be edgy like 210 on the seat on a1.875" intake valve, and a 1.570" exhaust valve.
As to why they fail, IDK

. I see some beehive springs lean when removed, and the spring seat is shiny about a third of the way around.
Lifters, I must be lucky, haven't had many failures come in, and I have some customers that are real hammers.
CVOSTU, big man ,cruises at 90 mph, likes to play, and a high mileage rider. 2 bikes NO lifter issues, CVO dual valve springs, high mileage.
John