Offgassing of li-ion batteries

Quickly wrapped up: is it normal for li-lion batteries to offgas solvents?

I have noticed the problem on 4 devices, which makes me question if it's really a battery defect, or normal?
I had an issue with old MacBook (M1). As soon as i started using it and it got warm, the smell - pungent, a bit rose-like was emitted, and allergy-like reaction starts on my eyes/throat/nose/skin. I have replaced it with MacBook M4, and same issue. It was worst when new, but didn't improve a lot over 6 months. I stopped using it and started to work on MacMini w/ external display, which doesn't cause the issue.

We don't have Apple store on island. I've opened apple support ticket, they asked to go to authorized service partner and check. They opened computer, took some photos and mentioned that "all looks normal, like new".

I'm observing same issue with phone. I had 1-year old iPhone 16, with battery in "Normal" state and >90% capacity. I called a friend from abroad who works with phone repair, described smell - and he quickly told me it's characteristic battery smell and I should replace it. I replaced phone and got new iPhone 17 pro - and guess what, same problem...

Tried different chargers, all from good certified brands. Different cables.

I started to keep phone in a sealed bag w/ activated carbon pellets. When it "sits" there for whole night, cold and not used, and I open it in the morning - I can definitetly smell it and have reaction. When I charge it or use intensively so it gets warm - same problem.

I noticed the same smell and alergic reaction when I come next to pawn shop with electronics, or phone repair point. I also noticed problem when a person was sitting next to me, charging his phone while playing a game.

I have several chemical allergies - to formaldehyde and methylisothiazolinone.
As far as I understand, some solvents (EMC, DMC) can react with air and produce HCHO.

I live in pretty warm and humid climate, on an island - so humidity is constantly between 60-80%, and ocean is close-by, so there might be some sea salt spray in the air. UV radiation is very strong here, up to UV-Index 12 in June.

Is my idea right, is this ethylmethylcarbonate / dimethylcarbonate, according to my description? Can they yield formaldehyde when they degrade in air?
Is that typical, that li-ion batteries offgas, even when new / almost new?

I don't believe I had such a bad luck that 2 MacBooks and two iPhones, new/almost new, had a deffective battery. But the smell issue is consistent, and so is allergic reaction. Living without laptop/mobile phone is a bit tricky in 21st century, especially for someone working in the IT area.

Any feedback/suggestions are welcome!