Game Version number: 1.2.1
Modded?: No

Issue Description:
Since the newest update whenever a player opens up the map in a multiplayer game where map markers have already been placed, part of the map marker's content gets visibly copied to the upper left corner of the map interface. Most of the time this is the author name and a small icon that is below every map marker (see the screenshots).

This unfortunately slows down the game a lot when there are a lot of map markers on the map, which is causing issues on big servers like WCS.
Furthermore, I believe it could be the case that this bug occurs every time when the map is opened, meaning the performance issue can become really severe.