Enable the "Edit Map" panel via:

Settings->Panels->Edit Maps

Then add a placemark via this panel by clicking the "Add Placemark" icon.

As a result a new item appears on the map: A red flag that has the name "Untitled Placemark". However if you look closely you'll see that there are two icons painted: a small one and a scaled up one on top. If you click next to the icon the bigger version disappears while the smaller ones remains. If you click the icon the bigger one on top of the smaller one reappears. The bigger version is supposed to indicate the selected state of the placemark. However it looks like it was forgotten to not paint the "unselected" smaller icon  during selection.

This task is about fixing the icon so that only the scaled up icon appears when the Placemark is selected and the other unscaled version of the icon only appears if the placemark is unselected.

The source code for this feature is located inside

/src/plugins/render/annotate/PlacemarkTextAnnotation.cpp