At end of as_c3map02 behind narrow desert-ish slope above power switching station with static discharge and 1 guard is small building with vortigaunt welcome party outside. Inside this building room a vent begin with a drop to another vent in lower level where transition to map as_c3map03 is located. For me map as_c3map03 was loaded with some bullsquid and barnacle noises - then game without any warning reloaded my previous as_c3map02 map save inside that last building room before exit vent. Went through exit vent again and experienced the same - map as_c3map03 is loaded, first sounds outside vent is heard then reload to my last save in as_c3map02 map happen. Tried several times - always the same. At end quit the game completely. Then started the game again and from main menu loaded as_c3map03 map from console with standard command

map as_c3map03

This helped with forced going back to as_c3map02. Dunno about the cause - are it is minor crash or wrong level transition trigger? Can you look into it?