The bug

Although /title text no longer renders in front of chat text in the latest snapshots, it still renders in front of the sidebar. This is not the case in previous versions.

How to reproduce

1. Use the following commands to create a scoreboard objective and show it in the sidebar:

   /scoreboard objectives add title dummy "Here is a long display name to make the sidebar wider!"
   /scoreboard objectives setdisplay sidebar title
   

2. Use another set of commands to set scores to at least eight fake players:

   /scoreboard players add $num1 title 0
   /scoreboard players add $num2 title 0
   /scoreboard players add $num3 title 0
   /scoreboard players add $num4 title 0
   /scoreboard players add $num5 title 0
   /scoreboard players add $num6 title 0
   /scoreboard players add $num7 title 0
   /scoreboard players add $num8 title 0
   

3. Use two commands to create title text in the screen:

   /title @s title "Here is a long title!"
   /title @s subtitle "Here is a long subtitle that renders wrong!"
   

   → You will notice that the title text renders in front of the sidebar.