[Bug] After Landscape editing, the Mouse freezes in UE4.16.2

my mouse freezes and my pc crashes when i click on landscape tab itself.

Hey there,
I have found a little Bug in UE4.16.2:
After releasing the Left-Mouse-Button to edit the Landscape (Sclulpt, Flatten, Paint etc.) the Mouse freezes for a second on small Landscapes, the bigger the Landscape, the longer the Mouse freezes (on my Landscape it freezes about 2-3sec).

Loading the Landscape-Tool for first time after Startup feels like it needs more Time than in 4.14.
The Landscape-Tool must be loaded now again after changing back to it^^

Maybe it´s because I have changed my active Engine from 4.14 to 4.16?
I don´t know if I have edited the Landscape anytime after changing the Version…

Okay, not sure if saying this three years after the question is asked is going to help, but I also had the issue where when I flatten the landscape the screen freezes. I found that by disabling the combined layers operation settings in the sculpt panel the issue is solved.