Shortly after my posting, Deutsche announced it would not call its perpetual bond, reports Reuters. One rationale for not calling could be that the bond would still be useful as bailinable debt.
An interesting trade-off has been made in favor of keeping old-style instruments over new, Bazel III-compliant, instruments.
One could argue that a choice favoring perpetuity has been made. However, I am not sure. Skipping a call at the first call moment does not necessarily prevent Deutsche form calling at a later stage.