When you have a sidebar with many items on it and the debug screen is opened, the layering of text is inconsistent. As per MC-62997, the overlapping is by design (though I think this should be reconsidered as there is now useful information on the right side - for example, an opacity slider like for chat but for the sidebar). However, parts of the debug text appears above or below the scoreboard text. If the overlapping is intentional, either the debug or sidebar should clearly be in the front.

For example, the underline of the "Targeted Block" and "Targeted Fluid" strings are drawn above the scoreboard text but seemingly below its background (as it is darkened). The scoreboard text is otherwise drawn above everything else, including the text of the debug screen. See attached image.

To reproduce this issue:

1. Populate your sidebar with values. In my case, I was playing on a server which was tracking the number of minutes online per player.
2. Set your GUI scale to 3, open the debug screen (F3) and look at a block
3. If needed, adjust your window height as appropriate until the sidebar and debug screen overlap. For me, I encountered this issue by playing with my window maximized leading to the 1920x1017 resolution shown in the attached image.

This is reproducible with other GUI scales and resolutions but I found the above to be the easiest to encounter.