When tab suggestions update while the cursor is hovering on a tab selection other than the first, two selections will be highlighted and the first suggestion will be shown in chat for a short time

To reproduce:

1. Type in /scoreboard objectives setdisplay s
2. Put your cursor over the second suggestion, idebar.team.aqua
3. Hit backspace
4. Observe both belowName and list be highlighted in the updated suggestion list and belowName being shown in chat for a very short time

This is easier to reproduce on lower framerates, and most visible when using "cinematic" 10 FPS (by changing Max Framerate in Options → Video settings)

This also happens when moving the mouse, although it's more subtle in that case.

See attached screenshot.