Periodic Posting GL entry date/period mismatch

I’ve got a Periodic Posting transaction that was made from the Capt COS/WIP rollup process - for outdated transactions.

The GL Report for Period 8 (Aug) shows:

But the WIP/Recon report shows the Tran and System Date to be 7/31

The thing that has our accounts worrying is that the $5,203.31 appears in July’s GL too.