It happened to me to, but I managed to kill the update halfway through, restarted my computer, re-installed the old version, and for now, it stays on the old version. I'm thinking that maybe some flag got set when the update started, and now it thinks it's updated, even when it's not ??? Maybe over the holiday break, when I have some time, because our company is going to be closed for the first time in memory (silver lining to the horrific pandemic situation), I'll read that other thread and understand more about what is going on, but for the moment, I have dodged the bullet...
And I'm being a lot better about downloading titles right away and version-proofing them.
Oh yeah, and I too had it set not to update, FWIW.