I have same problem as you with Tevii card - USB Tevii S660 and Dual TeviiS480. This problem occures with kernel >= 2.6.38.
The problem with green pixellatoin occures in channels in transponders with higher symbolrate, typically higher >= 30000 , e.g. transponders 0.8°W Thor 5 12015.00 H C16 Europe DVB-S2 8PSK 30000 3/4 Telenor, 66.8 Mbps NID:70 TID:41 0.8°W Thor 6 12034.00 V 17 K2 Europe DVB-S2 8PSK 30000 3/4 UPCD_Thor, 66.8 Mbps NID:1536 TID:705
Transponders with this parameters are also in other satellites, e.g. for SkyItaly ( 13E), Skylink (23E)
Problem occures in kernel 2.6.39. In this kernel is one of most great changes for modules - method ALGO_SW / vs. ALGO_HW for demodulator ...I contacted authors without any success .. Ivo Novak