Mata's strike on the stroke of half time was chalked off after officials determined, with the help of VAR, that he was offside.
However, a still image of the offside call which appeared on BT Sport showed wobbly lines being used to determine if Mata was beyond the last defender, prompting confusion and derision by fans and pundits.
To address the issue, Hawkeye issued a statement on Sunday which read: "A technical error led to an incorrect graphic being provided by Hawkeye to BT Sport on Saturday.
"To confirm, the VAR saw the correct image with the correct lines to make the decision. This was a case of the wrong image being provided to the broadcaster and we apologise."
Romelu Lukaku scored in each half for United to secure a quarter-final tie against Brighton & Hove Albion.