Google Adwords URL_PERFORMANCE_REPORT returns empty table

I'm using latest Adwords API for PHP, and my URL_PERFORMANCE_REPORT returns empty table in case if there are no active campaigns in the group.

I have no status predicates, just campaign ID predicate, and if there is at least one ongoing campaign, everything works fine, even if I get report on the ended campaign.

What could be the issue?

via Chebli Mohamed