While reporting an issue to tech support we found that the zecret -zn parameter affects the data that gets recorded by the profiler.
-zn is set by the "Allow specfial characters in names" option in the PDSOE run configurations,
With -zn all procedures are logged, (*)
Without -zn procedures staring with _ are hidden.
I strongly feel that the profiler should not hide time spent on _procedures. During profiling you are trying to find out which parts of the application cause performance issues. Hiding data here can lead to wrong conclusions.
If this behaviour is not changed this effect should at least be documented in the profiler. -zn may be secret but "Allow specfial characters in names" in run configurations is not.
(*) in 12.1 this can cause bug ADAS-20391 resulting in unreadable profile data.