Light leaks issue

There are light leaks between walls. I want to use plane-like walls, because it’s convenient to edit (you can see room and it’s containment). I tried switch MeshRenderer CastShadows On/Two Sided. I tried to change point light bias (zero value seems to thin light line). I tried to play with backface culling. All normals are good (Issues is even with simple planes). I tried to intersect walls (on screenshot). I tried to migrate URP/HDRP. How to fix this?! I use unity 2022.

It’s most likely shadow bias, it’s a property of the light itself. Reducing all biases to zero will prevent this leak, however it may produce inverse effect, shadows appearing on directly lit surfaces. Just tweak the bias values to find the compromise.

Another solution is to create walls with some real thickness, so that the biased shadow appears inside the wall.