No bug that I can see;

?5-2^2
 1st 2^2 = 4
 2nd 5-4 = 1

?-2^2
  1st -2^2 = 4

The - sign in 5-2^2 is subtraction wile in -2^2 it is a unary sign making 2 a negative number. In the second equation the - (unary sign) has precedence over the exponentiation while in the 5-2^2 the - is subtraction and it has a lower precedence from exponentiation so 2 is squared to 4 and then the subtraction is done 5-4 = 1.

I don't see any bug nor any inconsistency.