I couldn’t reproduce the same problem on a new simple scene.
Do you mind sending yours to support@chaosgroup.com? Please also mention this thread.
Thank you in advance!
Thanks for discovering this. Even creating a new dome light in the same scene has the same bais value. Surely It would make sense for the bias value of new lights to revert to the default, not the previously used value.
It does revert to the default value (which is 0.02 system units), but since you have meters for system units, but millimeters for display units you’re seeing 20 mm for the shadow bias.
Another option would be to add Shell modifier to the walls, at the moment they have no thickness and this is causing the leak.