logical "and" in search queries is treated as "or"

I see the wiki mentions that logicals are supported on the phylo-ws queries, i.e.

http://purl.org/phylo/treebase/dev/phylows/study/find?query=dcterms.contributor=Ronquist%20and%20dcterms.contributor=Hulesenbeck&format=rss1&recordSchema=tree

http://purl.org/phylo/treebase/dev/phylows/study/find?query=dcterms.contributor=Ronquist%20or%20dcterms.contributor=Hulesenbeck&format=rss1&recordSchema=tree

http://purl.org/phylo/treebase/dev/phylows/taxon/find?query=tb.title.taxon==%22Homo%20sapiens%22%20AND%20%22Pan%20troglodytes%22&format=rss1&recordSchema=tree

This works, except that it seems that "and" is always treated as "or".

Reported by: *anonymous