Market press presentation sort order

I have a site with product sort order in Marketpress settings set to 'price' 'ascending'.

Very recently (last couple of days) the products are out of sequence, the three recently added ones are ahead of the sorted prices.

I have tried descending, and I get the same issue (i.e. the 3 most recently added are at the end)

Please advise. In the meantime I'll get the client data over to a test system so I we can start investigating further.