Does anyone know why they got assigned to the Deluxe version versus the usual Basic version?

You may have had forms that required Deluxe; not everything is included in Basic. Without knowing more about your tax situation, it's impossible to say.

To go back to a lower version or the Free Edition you can try to clear and start over https://ttlc.intuit.com/community/using-turbotax/help/how-do-i-clear-and-start-over-in-turbotax-online/00/26444

In the Turbo Tax Free Edition, information that you can enter is limited now.  Why do I have to upgrade from the Free Edition?
https://ttlc.intuit.com/community/upgrading/help/why-do-i-have-to-upgrade-from-free-edition/00/26379

Or try the IRS Free File program
https://www.irs.gov/filing/free-file-do-your-federal-taxes-for-free