You are doing an excellent work. I have found only secondary issues, and not on every app that use your maps. But this seems to be a MAJOR ERROR!
E65 (Few years old - Highway) is actually A3 up to Kalambaka, and is extended North, (not finished) to meet A2 (E90). Not the old EO3 National road. (Google maps is correct here!).
EO3 is appeared as E65 on OSMand, Mapy.com, and Organic Maps.