Mold smell only at night in a specific area in my living room

[roni menkin]

I entered a new apartment a year ago, its a new building, 1 year old. The smell started last November, only at night, only in a specific place, not close to any plumbing or water line. At summer time around June the smell stopped. But now November, 1 year later it started again,only at night in the same place. I've tried calling a company that supposed to help with smells, but they couldn't think what can cause this. Can anyone help me? Advice me who should I contact? I tried telling the constructor manager. But he said he can't smell anything and didn't do anything. He came during the day when there's no smell. I'm so desperate 😭 It's driving me crazy Please help me 🙏