Level Lighting: Directional Light Going Through Level Assets

Hello everyone!

Our game has a lot of interior spaces being a multiplayer horror game. Haunted mansions, asylum interiors, etc. For the past few years our lighting has worked as intended, but after 5.1 I have been running into the issue that sometimes the directional light coming from our moon will light the interior of houses and tunnels etc. I tried baking the lighting assuming it was just an editor artifact, but it was not. Additionally, if I move the directional light it will ‘update’ and stop penetrating our architecture or landscape assets. But after a few edits in engine as I work on the maps… the moonlight will start ignoring intervening assets again. Some of these interior spaces are caves under landscape assets, others are building interiors. All of these locations have exterior objects that should prevent the moon light from going down into basements or the like.

Anyone having this problem, and if so any ideas on solutions? It seems to be something with UE5 since it has only started after we updated to 5.1

Even by just dropping in an unedited directional light… the light goes through all assets. Strangely it does shade each object, but it does not cast any shadows. It is set to cast shadows though, which is why I am confused. Seems to be an issue with directional light shadows.

What does your shadow scalability look like? Scalability is set to low in the pictures which could definitely remove global shadowcasting.