Workflow Update must not update last change date of a bug.

Changing the workflow updates lastchange date. so filters for monthly reports do not work correctly, because change of workflow is tagged as last change date. so our project admins have now the problem, that all non-closed issues are contained in report - e. g. 200 issues instead of expected 20 issues. so they have to sort the issues manually!

in my opinion a technical update must not be logged in a field, which tracks changes of contents.