Sending unknown packet error when joining a server with a resource pack twice in quick succession

If you join a server which downloads a resource pack twice in quick succession, this error is given:

Error sending packet serverbound/minecraft:resource_pack
io.netty.handler.codec.EncoderException: Sending unknown packet 'serverbound/minecraft:resource_pack' 

Reproduce:

1. Set up a Minecraft server
2. Point the resource-pack line in server.properties to a resource pack
3. Start the server
4. Join the server, cancel the connection shortly after (making sure the resource pack starts downloading), and then rejoin

It may take a few tries, but eventually you will get a "Failed to connect to the server" screen, showing the error.

After quickly looking at the recording I attached, it appears to error when timing the rejoin where the second resource pack starts downloading right as the first one finishes downloading. This could be wrong though.