Update 2: Legit resetting the binds, toggling the extension off and on again, and refreshing the page* often makes the shortcuts work again, this more likely a LingQ website/coding issue in my mind—not the Rooster Hotkeys extension.
P.S. I did the above again today and the go-to-next blue LingQ shortcut randomly worked again.
*I do this when the LingQ tab may have been open on a tab/idle too long.
P.P.S. Thanks for taking the time to reply @sarjag! It helped!! 