@chairraver I had the same problem with M570, I bought better switches and resoldered. Problem came out shortly after I bought it.
@chairraver I had to find invoice for them :) I bought D2F-T, they are louder but they work for 3 years and I had no problems with them. I don't know since when they started to put such poor switches, I had a Trackman Marble and it last for a long time until the roll broke. I bought M570 then and surprise :)
@michalb Thx.