Positive LFTs but negative PCR twice

[DaxtheDestroyer]

So confused! My DC tested positive on an LFT, we booked a PCR which was negative. When we got the result we checked with another LFT (completely different batch) which was even more strongly positive. Repeated PCR - negative again.
So what's going on? There must be something causing the positive LFTs, there are loads of cases at school at the moment. Anyone had this happen? Just so confused as to what's the right thing to do

Just to add that my DD tested positive again on an LFT this morning, so I've ordered a home PCR kit rather than the drive-through again.

We've all sent off postal PCRs now although none of the rest of us have had positive LFTs. Incidentally, thought it might be interesting to share a picture of what the positive LFT just before our positive PCR looked like - very faint! Weirdly the positives we had a couple of weeks back were very very strong ones.

Finally some action on this!
www.bbc.co.uk/news/live/uk-58922518
We've all been pinged as needing to retest again.

I ordered a postal one for DD which came back positive, I'm wondering if DH and I will be expected to redo our PCRs. No pings yet for us.