I got this from a lot of users and started to wonder about it myself. When updating the tree from one slot to the other, without removing the old one, updates are marked only as "N" in the "emerge -vup" output. perhaps this could be changed to "UN" or some other combination to signifiy that portage just doesn't suddenly install a lot of packages on a system? Reproducible: Always Steps to Reproduce: 1. 2. 3.
this may tie in with: bug #37721
personally I'd prefer a new indicator S.
This is released.