Those ICs can sometimes give false positives but I doubt two would. How long was your sample sat out until you used the FRER? This can make a difference. Also those strips are a little more sensitive than the FRER so it's possible you're only just meeting the threshold for the strips whilst not quite meeting it for the FRER yet, it could show up tomorrow or the following day. Some tests work for some, and some don't for others. Like many women see positives on FRER before ICs, but sometimes some will see positives on ICs first. I have always seen positives on ICs first, but unfortunately they all resulted in chemicals so my levels just didn't increase enough for a FRER to detect it most of the time. I would retest tomorrow with the ICs and a FRER, or the following day