Its not odd, because thats the way how the TDM-updater works.
Nice to know that TDM runs on your system.
And alt-tabbing in a linux distro is a known problem.
So the updater does incremental updates on a fresh system instead of just getting what is needed?
That update zips are more than 2 GiB by now. If you can avoid retrieving them, you should avoid retrieving them.