This is interesting, I’m experiencing the same issue:
shortcode is not generated in “Karte & Marker” while it is generated in other tabs like “Geotag speichern”. Tried in several browsers. Disables plugins in WordPress and Browser – no success.
OSM plugin: Version 5.4.3
Sorry for not closing this. In the end it turned out to be my mistake by confusing two plug-ins with similar names. The one I accidentally installed posted everthing automatically.