NPCs are faintly visible in MLO

Hi! I made my own MLO, and when I create NPCs inside, they disappear and reappear as my camera moves. What’s going on? I see that some solutions are to set up an interiorproxies.meta file, is that correct? I set it to be placed in the MLO directory without any effect.

My mlo path is:
E:\Games\txData\ESXLegacy_2A13F7.base\resources[maps]\xpmlo\stream