Like Raine

After some more testing it appears the issue was with the chiseled blocks on the far left and far right exterior front corners. I copied and pasted those 2 corner blocks in a creative world to inspect them and see no visual holes or gaps. I am thinking I used the tools from the mod "QP's Chisel tools" on those 2 blocks in particular and in combination with "chiseled blocked retention" somehow broke or corrupted these 2 blocks, it was also in a multiplayer world with high ping so that could have played a role.

Trying to understand why this room causes the firewood inside to burn when lighting the charcoal pit (ignore the dirt blocks inside, the charcoal pit was moved under the dirt in the meantime) I am using the mod Chiseled Block Retention so that it counts as a room internally The room gets filled with firewood 3x3x2 Here is video showing what the structure looks like