I noticed that if you join a server, where you must install prompted resource pack, and player dies before installing/disconnecting, then if you respawn, the message disappears and you do not longer need to install resource pack as no other message appears before reconnecting

I'm sorry for low quality of the video — had to lower it drastically in order to upload it here.

Edit 2: For it to be easier, here's the way to reproduce the bug

1. Install Minecraft Server
2. Change settings to make resource pack download a mandatory
3. Open Minecraft, connect to the server, but do not choose anything, when you will be asked to install resource pack
4. Using original Minecraft Server GUI (or CLI) kill the player.
5. Press "Respawn"

Expected behaviour:
The popup shows up again to ask player to install resource pack or disconnect.

Actual behaviour:
Nothing happens, player respawns and can play without installing resource pack.

Popup will be shown next time player connects to the server.