manual upgrades are discarded once a periodic upgrade is done

[mayeut]

Issue

Force a manual upgrade at t+0, this has setuptools released at t+0 which is now used by default because update triggered manually
At t+14, periodic update kicks in, setuptools released at t+0 won't be used anymore until t+28

I expect the setuptools released at t+0 to be installed after the periodic update kicks in.

Environment
code review only