For a long time I assumed it was just me and my web browser, but apparently this isn't just my problem. Bug #647902 is an example of a bug report where the Status/Resolution change and where this is not reported in a Comment. This apparently happens a lot. Perhaps adding a comment does make it log the status changes in a comment. Maybe it's some configuration option, or maybe it's a bug in bugzilla. No wonder people yell at me for making changes to bug reports without "explaining" them. :-)
After adding bug #647902 comment #3 the status changes are shown again! Very strange.
I see it below your summary change. Can you still reproduce it?