Smooth scroll stopped working

[xposionn]

Hi, how can I investigate the root cause of the smooth stopped working ? I don't know what data I can give you to help me with this.

The weird thing is that it suddenly stopped working on my computer but working in another computer. (I've tried to restart the pc and incognito as well)
Both scenarios has the similar browser, same monitor size and was logged in into the same Wordpress account .