if you've touched polynomials ever, you'd expect the exponent to be before the negation. If you write x³-x² you don't mean x³ + (-x)² = x³+x², you mean x³-(x²)
I was taught that negative numbers should be written as (-2) with the parentheses when using exponents. So I assume that the calculators are doing it right, or maybe it's just a measure against calculators doing it wrong? I cannot be sure. Also-2 = 0-2 so -2^2 = 0-2^2.