Drush features-diff produces weird results

in my given use case, the user interface tells me that everything is in state default.

but when i execture "drush fd myfeature" it will basically output, that it wants to remove all rules related export code from the module

shell$ drush fd austrofeedr_hochwasser_processor

Component: rules_config
< array(
...
RULES CONFIG
....
<   },
< )
---
> FALSE

fortunately, actually executing the command modify the feature's contents