Learn to Fix Light Leaks and Bake Quality Lightmass
Make sure to have thick walls when you build your model.
In some cases extra walls can help to prevent from light getting in.
Very important also to have enough “Indirect lighting bounces” – I’ve used 80+
and also use “Indirect lighting smoothness” – (smooth out your GI) – I’ve used 3
- If you bumped into some more light leaking issues – visit this