Strange OW v RTN availability

[Erico1875]

Searching EDI to PMI,Sat to Sat Aug/Sept to take advantage of the direct City Flyer flights.
RTN search shows no availability my dates either direct or indirect (which we are happy to do if necessary)
However.
Search one way, and 2 seats direct CE going out show up (which I’ve booked 👍)
Very strange.

[roger]

May be BA IT
Sometimes searching LON doesn’t give result but LHR does!