When using 'Set Input Mode to Game and UI' and enabling 'Use Mouse for Touch' this causes the Mouse to appear in different positions and change the direction the camera is facing. This is a regression from 4.19.2 (CL-4033788) as the issue didn't occur.
This issue was reported and tested in 4.20.2 (CL-4302132). It was reproduced in Main 4.21 (CL-4362844)
Results: The cursor changes positions and leaves the Viewport window after repeated clicks. It will also change camera positions depending on where you click.
Expected: After click, the mouse does not change position.
There's no existing public thread on this issue, so head over toAnswerHub just mention UE-64070 in the post.