Well, This usually happens when using the Tilde (~) key.
It's a "Continuous Duplicates Based on Mouse Movement" function and combined with Alt/Option, Shift/Command and spacebar you can create new and complex effects.
Are you sure your Tilde key is not pressed or locked somehow? Also, try drawing a circle while holding the Tilde key pressed...
I'm asking cause I don't know of a setting in Illustrator that will do this automatically...
PS: Here's an article where you can read about it.
I've solved the problem "replacing the preferences" with this solution:
- Close down Illustrator and press Ctrl+Alt+Shift/Cmd+Option+Shift before opening it again (easy but irreversible);
Thanks to this article and Jacob Bugge post: https://community.adobe.com/t5/illustrator/multiple-shapes-behaviour-in-the-shape-builder-tool/td-p/10840695
Hope does the same to you