In the 1st instance case underlying the BGH decision X ZR 51/13 "Einspritzventil", the plaintiff had argued that - besides of not being patentable - the patent did not enable the person skilled in the art to carry out the invention as defined in a certain auxiliary request without undue burden.
The Bundespatentgericht maintained the patent with this auxiliary request and rejected both the grounds of lacking patentability and lacking enablement. The latter rejection was a bit brief but formulated as a decision, not as an obiter dictum.
The lack of enablement then came into the focus of the appeal procedure and the patentee submitted that it should not have been admitted in the first instance as it was late filed and that it should not be admitted to the 2nd instance either because it was not pertinent (sachdienlich).
The BGH did not follow: Means of attack or defence or modifications of the action which hat not been rejected in the first instance as being late filed under § 83 Abs. 4 PatG cannot be rejected in the second instance, either. Once the first instance has decided on a matter, the matter is automatically subject-matter of the 2nd instance.