ESR ver. changed by itself to Quantum, and then changed back

[Odin2]

Not happy with the prospect of Quantum's changes, I never downloaded v. 57. Version 56 continued to work fine, but eventually I thought it would be wise to switch to ESR 52--which also worked just fine...until...

Yesterday Windows recommended Chkdsk, which I ran. Shortly afterward, I found I was running Fx 56! I therefore reinstalled ESR 52, but even though the About page confirmed it was ESR v. 52, just about everything else reflected a Quantum version. I tried to reinstall ESR 52, but the download would not install. Some hours later, everything (as far as I could see) changed back by itself to a true ESR 52, which I have used satisfactorily for a few hours.

(I don't have Fx set to update automatically.)

Can this behavior be explained? And what might I do to prevent it from happening again? Or to fix it in that eventuality?