When you have multiple server list entries with the same server name and server address and you play for example with the second one in the list and there download the server resource pack it will always change the resource pack settings for the first entry.
- Create the following server list entry twice
- Server name: cubecraft
- Server address: play.cubecraft.net
- Resource pack: Prompt
- Connect to the server using the second entry
- Use the "Travel" compass to get to "Lucky Islands" (sponge block)
- Accept the server resource pack
- Leave the server
- Inspect both server list entries but clicking "Edit"
→ You will notice that for the first server list entry the resource pack is enabled despite the fact that you connected using the second one
Based on 1.11.2 decompiled using MCP 9.35 rc1
The method net.minecraft.client.multiplayer.ServerList.saveSingleServer(ServerData) only uses the sever list entry name and IP to get the server the resource pack setting was changed for.