I don't know how that rumour started, but I challanged several forum members on the issue and not one of them could produce an incorrectly working example of SeedRnd in Blitz3D
It was a guy called Morduun who was on about it quite a lot.I never proved it either - in fact I argued the opposite. However, I did note that Blitz3D and BlitzPlus gave different results using identical test code.