I’ve experienced a rather odd behaviour when working with Work Items: in some, actually most cases changes do cause an increase of the Revision number, in other, looking at the History entries similiar cases, it does not increase the Work Item’s Rev field.

Following the link above will provide a little more insight into the ‘when’, but unfortunately not really the underlying why. Particularly, I’d much rather expect to have a consistent behavior for changes and their increase in revisions across all types of changes. But oh well.