I ran into a bug (I suppose) recently. After loading a *.3dm format mesh (triangulated irregular network with elevation data), with the Layer --> Add Layer --> Add Mesh Layer command, I put some data on it (2D water flow vectors and absolute speed to colorize it) and after created a Layout with a Map to export as pdf.
However, when I alter the Map Rotation property on a Map item in the Layout, the Mesh data disappears. So basically any rotation other than 0 degree makes the vectors, and colour disappear (it still shows the triangulation).
It shows again immediately after I put it back to 0 rotation.
Any ideas what's happening here?