Some Volumetric Lightmaps Samples change after unload sub level

Hello, i’ve a problem with volumetric samples. I have Persitent level with some sub levels (for light,mesh etc), they are always loaded. Have lightmass volume & character indirect on persitent with volumetric fog on. When i start playing (bug exist only on standalone mode) i have short cutscene. After that i want to unload that small level (170 static, some skeletal, 7~ lights). When i doing it (unstream level from level bp) i have random issue which going to take colour of my volumetric samples from different source of light which shouldnt be there. I can even see that after i unload my sub level my lights on level changes and some source of light are in diff place. I have directional & skylight static. It happens only in standalone and only when i unload my sub level but not always - reproduction 5/10