Did she test positive for the antibodies?
If not, dollars to donuts it was a false-positive.
The entire Scamdemic has been predicated on false-positives.
My wife did, when I didn’t the first time (and she had a symptom that same afternoon) and she did a second time nine days later, when she was continuing to have a fever that never went below 99.4 or so in the morning, then progressively up to as much as 101.4 by late evening.
The non-PCR tests are nearly 100% accurate when they diagnose a positive, while they are around 50% accurate when saying you are negative.
I surely had at least one false negative, out of my two COVID tests over that time. I got tested a second time the day my fever left me at only 97.2 F. I only had mild symptoms with a fever under 101 for less than two days.