Over filled reservoir

What is your question?

I may have over filled reservoir. I idled car to see if over heats. It didn't. I turned car off. It leaked coolant underneath car. But not over heating after son tried to find leak. Can not find leak. I'm not sure what to do next. Was told I have a overflow hose that will take over flow out. I'm not sure.

What makes this problem better or worse?

Only leaks when car is off

How long has your 2018 Buick Encore had this problem?

Started today