This message is due to the :Top12 minicalendar modifier being incompatible with the current date offset minicalendar modifier.
The combination of these 2 Minicalendar Modifiers makes no sense, since the :Top12 modifier is used for square minicalendars, while the date offset modifiers are used for single-line minicalendars.
Topic 177345, last updated on 19-Apr-2020