Mouse cursor disappeared on external display when rotated

I have a MacBook Pro 13-inch 2017.
My macOS High Sierra has the version 10.13.4 (17E199).

So my problem is that, after the last macOS update, my 2nd external monitor doesn't show the mouse cursor anymore. This monitor was rotated 90°.

What I tried:

• rebooting
• making the cursor bigger (read that tip somewhere)
• when shaking the mouse the cursor is shown in big but the hides again
• when rotations is set is to default the cursor is there again
• when in any rotation both external monitors doesn't show the cursor

So anybody has a idea to fix that?