I see multiple invalid mappings after updating a task
HINTS
When you remove and add a user interface from a task via the task editor all existing mappings based on the data structures will get invalidated as the internal data types are removed and new ones (which look similar, but are different) are added. Thus all mappings point to 'dead ends'.
The following note describes a way to bypass this behavior and what to do in the case you already encountered the behavior and want to get rid of the errors:
http://service.sap.com/sap/support/notes/1349644