It looks like there is some repetition in the binary representation to me. English language phrases in UTF-8 are not going to look random.

It is very easy for short strings to pass most of the tests.

These days PractRand seems to be the best randomness test suite: https://pracrand.sourceforge.net/

Somewhat offtopic, but in case anyone is curious my random stream was a little daemon process I wrote. The problem was around 2000-ish Linux had a weakness in /dev/random where it would read from things like keyboard timings and feed them in as sources of entropy into a cryptographic sponge function that would write them into /dev/random and increase the entropy count. If you had a long-running Linux server, it didn't have anyone typing on the keyboard and the other entropy sources didn't generate that much entropy so your server would eventually run out of entropy in the pool and then would block when people tried to initiate ssl connections.

So I wrote a little "additional entropy daemon" that would read things like CPU temperature fluctuations, signal noise on soundcards if installed etc (I forget them all exactly but there were a few), "bleach them" so they had reasonable statistical properties (eg the soundcard one before bleaching was almost all zeros with just occasional spikes in it so you want that to be normalized a bit) mix them together somewhat chaotically and then feed them into the sponge function with a relatively low entropy estimate. This meant our servers wouldn't block. I used diehard to test the randomness of the sources I was using before and after the mixing.

The bug got fixed and people generally got comfortable using /dev/urandom rather than /dev/random, so my little process moved on to live on a farm with other daemon processes that were retired from use. I don't even have the source code any more.