Measures lost after upgrading to 7.1

One of my ad hoc views and logically as well the report based on it do not function anymore after upgrading to 7.1

error : the following fields and/or measures no longer exist in the data

I can still see those measures in the resources of the ad hoc view in the TopicJRXML.data file

another ad hov view and related report without measures works as good as before

is this due to the upgrade ? , different way of handling measures ? something else ?