Collision interpenetrating between 2 meshes

I’ve been kinda ignoring this problem but now I really need to fix it and can’t seem to find the solution anywhere.

I have 2 meshes, both using box colliders and the top one using gravity and no idea why, they always interpenetrate slightly when the simulation starts. I even tried increasing the box size and it kind of helps but it causes other issues with shadows etc.

I’m pretty sure there must be a way for the collision detection to be more precise? Could it be a scale issue?

Just went extreme and set the “Min Penetration For Penalty” to 0.001 and seems to have worked. Hope there are no issues for the value being so low…