Though Corona renderer is natively supported by Forest Pack our Presets included in Lite / Pro version contain materials for following renderers: Standard, Mental Ray, VRay, Octane Render, Thea Render. As showing on screenshot you can find the list under Options part on the bottom of Library Browser.
By default the Automatic Selector is activated and when placing any preset into the scene it recognise the render engine used in the scene and assign corresponding material. Unfortunately, as there is no Corona material prepared, so it assigns Standard one.
Anyway, once changed this material in the scene (in your case to Corona one) you can change the behaviour while reloading the preset using Library Browser from Replace from Library to Use Scene Material or Ask to user.
Hope this helps you. Have a nice day.