Technical problems with my second System 8

Dear System 8 experts. I recently purchased System 8. The first one I received had a defect in the start up and stopped with only Roland in the display. The people at Roland could not fix it and they did send me a new one. The Second System 8 has another significant defect. Without doing any changes on the buttons the display switches between different settings Osc2 4 feet or 16 feet then back to the patch name again and again. Then sound suddenly goes up an octave with a different feel in the sound. I will once more return it but would like to hear from you guys if the System 8 is full of such issues. Is it just a plastic thing with poor quality or am I extremely unlucky.