Since both queries have the same length, their results will be both correct or both flipped. If the 1 is in $[1, n/2]$, the only 1 in $a$ will be in exactly one of the queries, so they will have different results. If not, the two results will be both 0 if not flipped or both 1 if flipped.
Since both queries have the same length, their results will be both correct or both flipped. If the 1 is in $[1, n/2]$, the only 1 in $a$ will be in exactly one of the queries, so they will have different results. If not, the two results will be both 0 if not flipped or both 1 if flipped.