WP 5.0 Classic Editor bug

I am currently using WP 5.1.1 with the classic editor installed and experiencing issues when highlighting parts of content in the visual editor, it is also highlighting parts of an inforgrapahic in the text editor side which is not visible when you are in the visual side.

I did not have this issue in previous WP versions? Is this a bug that could be possible fixed in the WP 5.2 release please?