Its a new heads up to me, I'm still digesting it and could be misinterpretting the whole situation. Here was the first heads up for me, posted by Sean Lange:

http://www.sqlservercentral.com/Forums/FindPost1369994.aspx

which refers to

http://support.microsoft.com/kb/307487

which coming direct from Microsoft does give some legitimacy to the issue. I may have spoken too soon about it "not being considered a bug" though as books on line (on my install) gives:

"The database being shrunk does not have to be in single user mode; other users can be working in the database when it is shrunk. This includes system databases."

so given the conflicting info, maybe the situation is not quite "not a bug", but I certainly am at least now aware of the issue.