Problem with the steel clutch plates

[Mc_Grath]

I have an 2011 300ec. With 70 hours on the bike, the clutch started to work weird. When starting, it would be like an on/off switch and makin a light sound, so I opened it, when the clutch heated (and I mean the cluth, not the bike) it started to work better, almost right; but then again, when cooling down it started to work funny again. The basket had some little dents but nothing important, so I checked the steel disks and they were out bended of spects, if I put them over a glass, I could put a 0.4mm gauge under them. I changed them for the original steel plates and then it worked great, like a new bike.... until 5 more hours of use. Now the clutch is acting the same as before. Only 5 more hours and I suspect the plates are bend again. Any one have an idea about why they would bend? I did not change the friction plates but they seemed to be ok..

Thanks.
Bernardo.