postgresql random() bug?

select random() * 999 + 111 from generate_series(1,10)

690,046183290426
983,732229881454
1091,53674799064
659,380498787854
398,545482470188
775,65887248842
1044,79942638567
173,288027528208
584,690435883589
522,077123570256

Two values are over 999!

This one works fine: select random() * 9 + 1 from generate_series(1,10)

PostgreSQL 9.3.5 on x86_64-unknown-linux-gnu, compiled by gcc (Ubuntu 4.8.2-19ubuntu1) 4.8.2, 64-bit

Is that a bug?

Thanks Joe