Hi,
Thanks, I found the issue. The mass actions filter/action on the order status wouldn't work properly when the namekey of the order status was different from the name of the order status, and you were exactly in that case with the "Review" / "Prodcut Review" order status.
So you have two solutions:
- either recreate / modify your order status to have the same namekey/name.
- or download again the install package of the 3.5.1 and install it again to get the patch
AND then in both cases, edit again your mass action, select again the status if necessary and SAVE the mass action once to register the change.