Problem Overview
The REST API of the CRUD webservice A&AI Resources is not consistent under concurrent access to the same entity (calls using the same ID). If multiple requests modify the same entity the result is undetermined. The worst case behaviour observed is when concurrent access produces duplicates of that entity - the result is that no further REST queries (GET/POST/DELETE ...) to this entity are possible and the entity become inaccessible. Afterwards only a manual intervention in the database can restore proper service behaviour.