[gentoo-user] emerge @ world -> @preserved-rebuild -> @preserved-rebuild -> what next?

[Mark Knecht]

So on one machine yesterday I did emerge -DuN @world which then
suggested the need for emerge @preserved-rebuild which I did over
night. This morning it was finished but suggested the need for a
second emerge @preserved-rebuild. As I don't need the machine right
now I kicked it off and will check it again later but I'm wondering
why in the world it needs to do this twice, compiling 52 packages the
first time and 50 packages the second time where most of the packages
in the first list were in the second list?

Is this setting up for an endless loop?

Most of the packages were part of Gnome or XFCE4.

Cheers,
Mark