I have found another example that gives the Another Order Reject … 2 Orders same time, same direction, same Market on 2 separate Systems … 1 (of the 2) Order gets rejected and then the (rejected) Order gets executed some millseconds later!

Note the times on the Orders List screen shots.

So it seems the words in the Another Order Reject message are correct! 🙂

And also PRT cannot execute 2 Orders same time, same direction, same Market, SAME PLATFORM??