Hi everyone, I've created a database backup of my production environment and I'm now using this for my testing environment to make testing a bit easier. Unfortunately I can't open a single node in the backoffice. For each node I get an error "Sequence contains more than one matching element" in my console. However, I can't find anything in the logs and have no idea how this error can happen. I've deleted the TEMP folder, rebuild all indices, reloaded the cache etc. Does anyone know how I can fix this error? When I use this database locally everything works fine which is why I believe that something is wrong with the cache or files on the server.