I can't select the curvature tool without an asterisk alongside it, so instead of adjusting anchor points, it creates new paths. Caps lock is off, and it's been working fine until today.
Are there any recent changes made to your system? For example, any antivirus, system updates, plugins, or web extensions installed recently.
A small video demonstrating the issue could be really helpful.
Does resetting Illustrator Preferences ( https://helpx.adobe.com/illustrator/using/setting-preferences.html) help to resolve the issue? Disclaimer: Please note that resetting preferences will remove all the custom settings, and Illustrator will launch with default settings. You can also take a backup of the folders in case you want to. Location is mentioned in the article.