As I said, we did some cleanup in the pool. There were many days on May that the pool was mining in a fork. So the blocks that looks that are there, are not the blocks that were mined actually by the pool, but the new ones (block height was off by several 10ths of thousands back then).
In other words, if you don't see the transaction in the pool, that means that this transaction took place (along with the mined blocks) in the wrong chain, thus they are invalidated as soon as we tried to clean the net from the forks.

When wallets mine in the wrong fork, it's normal that those blocks are not valid when the wallets return to the correct blockchain fork. It's like they never existed. The same of course applies for the coins that were rewarded for the discovery of those blocks and the same for the transactions that were included in those blocks.