I cut on the floor on an OLFA mat, with OLFA blades, it's not the same pack as I have used three different packs, all OLFA and all from that yellow case they come in.
Could it be that the blades are being damaged by a nick in the OLFA mat? Because there is one nick in the mat for sure and although the nick is not causing my troubles (I tried using the back of the mat and the blades still had the nicks), could it be that the nick in the mat is damaging the blades?
I can't see how a nick in the soft mat could harm the steel blades?