I am having the same problem, Everything was cleared and reconciled up to 31/3/26 and now after the last update nothing is reconciled anymore and there are a number of old transactions from that same financial year that are not saying they are 'unmatched'?? this is not possible.
Does anyone have an answer, I can find the old transactions in the transactions list but as soon as I go to reconcile they disappear, and I can't enter the correct dates in the reconciliation screen to bring them up, it is only allowing very strange dates i.e. 25/3 instead of 31/3??