Peter, have you tried keeping all maps but switching off using them all at once?
OSM Scout Server -> Settings -> Geocoder-NLP -> Search all available maps
When switched off, it enables a drop-down menu at the top of main OSM Scout Server's screen to select your currently used map.
Not sure if it makes any difference, though. The option's name suggests that it only applies for searching and I am sure rinivus would have mentioned it if he believed it was worth it, but... the map selection in the main screen does not mention any ifs or buts so I would try it