You can indeed give your worms to much coffee grounds.
While coffee grounds are good for worms, giving the worms too many or too much coffee grounds can actually harm the worms or even kill the worms.
Worms love coffee grounds, when used in small and diluted amounts, but too many coffee grounds can create a hot, compact and overly acidic environment, which causes what's known as "strings of pearls" syndrome and can also drive the worms out of the bin.
When using coffee grounds for worms, the coffee grounds should not make up more than 1/8th to 1/4th of the worms total bedding and feed material.
The coffee grounds for worms, should also be used in moderated and treated as a supplement for the worms and not a primary food source for the worms.
And when using coffee grounds for your worms, always mix the coffee grounds with carbon rich materials such as shredded cardboard, dry leaves or paper to help balance the pH and nitrogen.
And only use brewed and cooled coffee grounds as fresh coffee grounds can cause the worms bin to overheat.
And you can also mix some crushed eggshells in with the coffee grounds for the worms, to help counteract the acidity of the coffee grounds.
When using coffee grounds for your worms, you should also monitor the worms behavior and if the worms are trying escape from the bin, or the worms are gathered in tight and stringy balls on the surface, you should reduce the amount of coffee grounds used for the worms.
If the bin for the worms is overwhelmed with coffee grounds, it's also good to remove any excess coffee grounds and replace it with some fresh and neutral bedding.