Ah, if they are new, you need to search on here for the solution..which I read here sometime last year, I think. The narative concerns complaints about new visors not fitting tightly, but was resolved by an explanation wrt fitting procedure.
The tube / rod fit is not fully round but slightly eliptical, and the tubes need to be slipped over the rods at the correct angle on initial fitting, or you can suffer these problems.
Perhaps others can remeber the Topic and posts and help find it.
Good luck
Paul