Scoops appear twice in 'best scoops' block

We post scoops to groups and for some reason (which I have not investigated), scoops were listed twice in the "best scoops" block.

I modified the query in the file drigg/drigg_blocks/drigg_blocks.module:

$query="SELECT * FROM {node} n LEFT JOIN {votingapi_cache} vc ON n.nid = vc.content_id WHERE ".drigg_votingapi_query('vc')." AND vc.value <> 0 AND n.created > UNIX_TIMESTAMP(CURRENT_TIMESTAMP()) - 60*60*".variable_get("drigg_block_${var_name}_days", 48)." $only_promoted AND n.status=1 GROUP BY n.nid ORDER BY vc.value DESC LIMIT %d";

to:

$query="SELECT * FROM {node} n LEFT JOIN {votingapi_cache} vc ON n.nid = vc.content_id WHERE ".drigg_votingapi_query('vc')." AND vc.value <> 0 AND n.created > UNIX_TIMESTAMP(CURRENT_TIMESTAMP()) - 60*60*".variable_get("drigg_block_${var_name}_days", 48)." $only_promoted AND n.status=1 GROUP BY n.nid ORDER BY vc.value DESC LIMIT %d";

The addition is the GROUP BY clause.

Is this the correct way of solving my problem? If not, do you have a suggestion were to start looking on WHY the posts appear twice?

Bart.