Custom shuffle function stopped working in 9.6

[Alexander Farber <alexander.farber@xxxxxxxxx>]

Good evening,

after switching to 9.6.2 from 9.5.3 the following custom function has stopped working:

CREATE OR REPLACE FUNCTION words_shuffle(in_array varchar[])

        RETURNS varchar[] AS

$func$

        SELECT array_agg(letters.x) FROM 

        (SELECT UNNEST(in_array) x ORDER BY RANDOM()) letters;

$func$ LANGUAGE sql STABLE;

In 9.5.3 it was shuffling characters:

words=> select words_shuffle(ARRAY['a','b','c','d','e','f']);

 words_shuffle 

---------------

 {c,d,b,a,e,f}

(1 row)

But in 9.6.2 it has stopped doing so:

words=> select words_shuffle(ARRAY['a','b','c','d','e','f']);

 words_shuffle 

---------------

 {a,b,c,d,e,f}

(1 row)

Any suggestions for a better shuffling function please?

Regards

Alex