eZRecommendation 1.1 fails to present results for top_clicked or top_clicked_article in eZ Publish 4.7

The respsonse to
ezjscore/call/ezrecommendation::getrecommendations::176::top_clicked_article::0::1
is always

steps to reproduce

. configure eZ Publish 4.7 with eZ Recommendation 1.1
. setup some articles and submit them for posterior recommendation
. (wait for the next day to make sure the articles have been processed. check in eZ Recommendation Service Statistics, on setup, to make sure they've been properly accounted for)
. authenticated in the front end, access an article with the top_clicked_article recommendation tag
. no recommendation will be showed and apache log should present a report on a foreach cycle failing to execute

note: In order for my test eZP4.7 to stop working I had to clear all browser cache and to login with a new user in the front end. I believe the requirement to login might be related to a some quirk in my configuration, but until I cleared the cache it all seemed to work properly (as it had been working for a few weeks)