Palidin, I ordered the FDPSR1 blade. I have used these for some time and immediately noticed something wrong when I received the blades. They did exactly as you described. Jumping, burning, and seemed quite dull. I called WTB and they said they had not had any complaints and to try a couple more dozen, which I did. Still the same results. I called WTB and she said they had more complaints and they would get in touch with the manufacture. About four days later I received new blades to replace the bad ones and a phone call to see if I was satisfied.. These seem to be okay. I would definitely give them a call.
grizz