Resource packs continue downloading after disconnect

Minecraft appears to continue downloading resource packs until finished or the filesize cap is reached, regardless of if the user in question is still connected to the server that sent the pack. For instance,

is the filesize just after disconnecting from a server. After several minute of being disconnected to that server and connected to an entirely separate server, this was the filesize:

This can be reproduced by downloading a large zip file as a resource pack, disconnecting from the server sending it, and connecting to another, non-resource pack server. (I haven't tested it on other servers with resource packs)