Possibly but Great Railway Journeys isn't mentioned in the Conflict Checker emaildo you use accurate recording? there may be a problem at 22-00 if portillo runs late.
A long time ago I had one or two conflict reports from RS which weren't. I just put them down to a glitch in either RS or the broadcaster data.
The algorithm that RS uses isn't perfect and can sometimes flag things like this as conflicts when they aren't. Improvements are on my to-do list!