dynamic bolt groups are empty

[mathse]

My inventory.yaml file has a couple of groups, some static with specifically named servers and some groups are based on a puppetdb query. Those dynamic groups are listed but with zero nodes.
All groups with specific servers are properly shown with their node numbers.

[mathse]

turns out, the very same query in pabawi will result in another list of nodes in my puppetboard - both sharing the same puppetdb
pababi -> 2 nodes
puppetboard -> 64 nodes
puppetdb via curl -> 64 nodes

here ist my query

inventory[certname] { certname ~ 'ceph' }

am i doing something wrong?