The only possible explanation is that the bootup was modified. I can't think of anything else.
My boot has never been modified at all. I originally bought this PS3 from eBay last summer and the firmware was 1.92 OFW. I then did the Geohot CFW 3.55 and then got what I wanted from it. Finally, I updated to OFW. I have never modified the bootup at all.
I wish I could listen to it again because it was tight. I tried turning my PS3 off and turning it back on thinking it might do it again, but it didn't.