Bex Query changed - Change source wizard not working

Hi.

During our last release we exchanged some objects from a Bex Query and now have to change also he BO report, because we get the error "Cannot get the cube from the connection: ...." because of the missing Nav. Attribute. To solve this issue I like to use the change source wizard to map the new fields which are available in the query now.

But the wizard shows up a blank page only. It run fine on reports that does not have this error but it should be possible to change the source even if the source layer is not available anymore...??? 😭

Cheers,

Nils