Stay there, youre good.
2000-2500 (specify in post)
Say an active, weightlifting person is eating their daily required calories, which is 1,800.
That person then drops to eating 1,400 calories/day.
Maybe they will lose some fat, but it's also possible that instead of requiring 1,800 calories, the body will downregulate some processes so that it only needs to expend 1,400 which allows the body to regain homeostatis. For example, immune activity may decrease, hair may not grow as fast or full, fertility/virility might be reduced, body temperature might be lowered, etc...
Now the person's daily requirement is 1,400 calories, and returning to the previous requirement of 1,800 may produce fat gain.
Or, maybe while eating 1,400 calories, the person has less energy, and therefore reduces activity levels (from reading Lyle McDonald's Body Recomposition articles, this is extremely common, and most people aren't even aware that they are being less active).
Now the person has a calorie requirement of 1,400 calories, but this is based on previous activity levels, which have unknowingly decreased. This leads to fat gain because there is a surplus when the person is assuming there is a deficit.