cts:uris score-random option does not returned random URIs

In the cts:uris function I added "score-random" to the option of the query but it returns the same results.

Here's my sample query

cts:uris("",("score-random"), cts:collection-query('my-collection')) [1 to 10]

In contrast to cts:search which returns random results

cts:search(collection("my-collection"), cts:and-query(()), ("score-random"))[1 to 10] ! document-uri(.)