For a hash of N hex digit. The probably to have a single e and the rest decimal is N*10^(N-1)/16^N With 10 hex digit like on the blog, that'd be 0.9% so about

For a hash of N hex digit. The probably to have a single e and the rest decimal is N*10^(N-1)/16^N With 10 hex digit like on the blog, that'd be 0.9% so about once every 100 builds With full 40 digit: 2.7e-8 so about once every 100M builds Assuming my math is correct.