ANC changes EQ?

I purchased the Nothing Headphone 1 last week and I've noticed that turning off the ANC significantly changes the sound even in a quiet room. The bass seems to be boosted and the sound just changes drastically.

Is this just a common ANC thing? I've come from years of IEMs with proper foam tips that isolates against sound waaay better than ANC so I've never really used modern ANC. In a crowded space I would understand why the sound might change when turning on ANC. But the sound changes so drastically even in an quiet room.