This is spammed when I try to start the game with 5zig, and the game freezes (seems to be a conflict between 5zig and a very simple mod I have)

[20:52:39] [5zig Netty Client/INFO] [5zig/]: Connected after 0 tries!
[20:52:39] [5zig Netty Client/DEBUG] [5zig/]: IN | eu.the5zig.mod.chat.network.packets.PacketClientStats@7a06d0eb (2 bytes)
[20:52:39] [5zig Netty Client/DEBUG] [5zig/]: OUT| eu.the5zig.mod.chat.network.packets.PacketClientStats@7ae8d943 (54 bytes)
[20:52:39] [5zig Netty Client/DEBUG] [5zig/]: IN | eu.the5zig.mod.chat.network.packets.PacketSettings@52687456 (3 bytes)
[20:52:39] [5zig Netty Client/DEBUG] [5zig/]: IN | eu.the5zig.mod.chat.network.packets.PacketProfile@28abd03 (64 bytes)
[20:52:39] [5zig Netty Client/DEBUG] [5zig/]: IN | eu.the5zig.mod.chat.network.packets.PacketFriendRequestList@3b923c49 (5 bytes)
[20:52:39] [5zig Netty Client/DEBUG] [5zig/]: IN | eu.the5zig.mod.chat.network.packets.PacketFriendList@220afa6 (5 bytes)
[20:52:43] [5zig Netty Client/DEBUG] [5zig/]: IN | eu.the5zig.mod.chat.network.packets.PacketHeartbeat@2c915af1 (5 bytes)
[20:52:43] [5zig Netty Client/DEBUG] [5zig/]: OUT| eu.the5zig.mod.chat.network.packets.PacketHeartbeat@2ee7f53a (5 bytes)
[20:52:48] [5zig Netty Client/DEBUG] [5zig/]: IN | eu.the5zig.mod.chat.network.packets.PacketHeartbeat@293d32df (5 bytes)
[20:52:48] [5zig Netty Client/DEBUG] [5zig/]: OUT| eu.the5zig.mod.chat.network.packets.PacketHeartbeat@fddb3db (5 bytes)
[20:52:53] [5zig Netty Client/DEBUG] [5zig/]: IN | eu.the5zig.mod.chat.network.packets.PacketHeartbeat@48a6b96d (5 bytes)
[20:52:53] [5zig Netty Client/DEBUG] [5zig/]: OUT| eu.the5zig.mod.chat.network.packets.PacketHeartbeat@59f9cb66 (5 bytes)
[20:52:58] [5zig Netty Client/DEBUG] [5zig/]: IN | eu.the5zig.mod.chat.network.packets.PacketHeartbeat@1912b14c (5 bytes)
[20:52:58] [5zig Netty Client/DEBUG] [5zig/]: OUT| eu.the5zig.mod.chat.network.packets.PacketHeartbeat@7bb38ade (5 bytes)
[20:53:03] [5zig Netty Client/DEBUG] [5zig/]: IN | eu.the5zig.mod.chat.network.packets.PacketHeartbeat@6233914 (5 bytes)
[20:53:03] [5zig Netty Client/DEBUG] [5zig/]: OUT| eu.the5zig.mod.chat.network.packets.PacketHeartbeat@1196704d (5 bytes)
[20:53:08] [5zig Netty Client/DEBUG] [5zig/]: IN | eu.the5zig.mod.chat.network.packets.PacketHeartbeat@1d022be2 (5 bytes)
[20:53:08] [5zig Netty Client/DEBUG] [5zig/]: OUT| eu.the5zig.mod.chat.network.packets.PacketHeartbeat@7a00a7e6 (5 bytes)
[20:53:13] [5zig Netty Client/DEBUG] [5zig/]: IN | eu.the5zig.mod.chat.network.packets.PacketHeartbeat@6574da2b (5 bytes)
[20:53:13] [5zig Netty Client/DEBUG] [5zig/]: OUT| eu.the5zig.mod.chat.network.packets.PacketHeartbeat@4742cad0 (5 bytes)
[20:53:18] [5zig Netty Client/DEBUG] [5zig/]: IN | eu.the5zig.mod.chat.network.packets.PacketHeartbeat@4b93b4e1 (5 bytes)
[20:53:18] [5zig Netty Client/DEBUG] [5zig/]: OUT| eu.the5zig.mod.chat.network.packets.PacketHeartbeat@34d315e2 (5 bytes)
[20:53:23] [5zig Netty Client/DEBUG] [5zig/]: IN | eu.the5zig.mod.chat.network.packets.PacketHeartbeat@773534d1 (5 bytes)
[20:53:23] [5zig Netty Client/DEBUG] [5zig/]: OUT| eu.the5zig.mod.chat.network.packets.PacketHeartbeat@26f064ad (5 bytes)
[20:53:28] [5zig Netty Client/DEBUG] [5zig/]: IN | eu.the5zig.mod.chat.network.packets.PacketHeartbeat@7012f82e (5 bytes)
[20:53:28] [5zig Netty Client/DEBUG] [5zig/]: OUT| eu.the5zig.mod.chat.network.packets.PacketHeartbeat@5cc28fcb (5 bytes)
[20:53:33] [5zig Netty Client/DEBUG] [5zig/]: IN | eu.the5zig.mod.chat.network.packets.PacketHeartbeat@28fbb3e (5 bytes)
[20:53:33] [5zig Netty Client/DEBUG] [5zig/]: OUT| eu.the5zig.mod.chat.network.packets.PacketHeartbeat@277f62ce (5 bytes)
[20:53:38] [5zig Netty Client/DEBUG] [5zig/]: IN | eu.the5zig.mod.chat.network.packets.PacketHeartbeat@404b3d87 (5 bytes)
[20:53:38] [5zig Netty Client/DEBUG] [5zig/]: OUT| eu.the5zig.mod.chat.network.packets.PacketHeartbeat@83f4e92 (5 bytes)
[20:53:43] [5zig Netty Client/DEBUG] [5zig/]: IN | eu.the5zig.mod.chat.network.packets.PacketHeartbeat@771652e0 (5 bytes)
[20:53:43] [5zig Netty Client/DEBUG] [5zig/]: OUT| eu.the5zig.mod.chat.network.packets.PacketHeartbeat@2ba327de (5 bytes)
[20:53:48] [5zig Netty Client/DEBUG] [5zig/]: IN | eu.the5zig.mod.chat.network.packets.PacketHeartbeat@329d9028 (5 bytes)
[20:53:48] [5zig Netty Client/DEBUG] [5zig/]: OUT| eu.the5zig.mod.chat.network.packets.PacketHeartbeat@40240337 (5 bytes)
[20:53:53] [5zig Netty Client/DEBUG] [5zig/]: IN | eu.the5zig.mod.chat.network.packets.PacketHeartbeat@560c881 (5 bytes)
[20:53:53] [5zig Netty Client/DEBUG] [5zig/]: OUT| eu.the5zig.mod.chat.network.packets.PacketHeartbeat@374f8224 (5 bytes)
[20:53:58] [5zig Netty Client/DEBUG] [5zig/]: IN | eu.the5zig.mod.chat.network.packets.PacketHeartbeat@698d5835 (5 bytes)
[20:53:58] [5zig Netty Client/DEBUG] [5zig/]: OUT| eu.the5zig.mod.chat.network.packets.PacketHeartbeat@950d388 (5 bytes)
[20:54:03] [5zig Netty Client/DEBUG] [5zig/]: IN | eu.the5zig.mod.chat.network.packets.PacketHeartbeat@a7726e3 (5 bytes)
[20:54:03] [5zig Netty Client/DEBUG] [5zig/]: OUT| eu.the5zig.mod.chat.network.packets.PacketHeartbeat@41e2cb2b (5 bytes)
[20:54:08] [5zig Netty Client/DEBUG] [5zig/]: IN | eu.the5zig.mod.chat.network.packets.PacketHeartbeat@42ad7fd2 (5 bytes)
[20:54:08] [5zig Netty Client/DEBUG] [5zig/]: OUT| eu.the5zig.mod.chat.network.packets.PacketHeartbeat@4d6e289c (5 bytes)
[20:54:13] [5zig Netty Client/DEBUG] [5zig/]: IN | eu.the5zig.mod.chat.network.packets.PacketHeartbeat@7e1d5fec (5 bytes)
[20:54:13] [5zig Netty Client/DEBUG] [5zig/]: OUT| eu.the5zig.mod.chat.network.packets.PacketHeartbeat@29f17897 (5 bytes)
[20:54:18] [5zig Netty Client/DEBUG] [5zig/]: IN | eu.the5zig.mod.chat.network.packets.PacketHeartbeat@8bc194 (5 bytes)
[20:54:18] [5zig Netty Client/DEBUG] [5zig/]: OUT| eu.the5zig.mod.chat.network.packets.PacketHeartbeat@3c9d23d1 (5 bytes)
[20:54:23] [5zig Netty Client/DEBUG] [5zig/]: IN | eu.the5zig.mod.chat.network.packets.PacketHeartbeat@28ebf991 (5 bytes)
[20:54:23] [5zig Netty Client/DEBUG] [5zig/]: OUT| eu.the5zig.mod.chat.network.packets.PacketHeartbeat@a7c19db (5 bytes)
[20:54:28] [5zig Netty Client/DEBUG] [5zig/]: IN | eu.the5zig.mod.chat.network.packets.PacketHeartbeat@54a5fe61 (5 bytes)
[20:54:28] [5zig Netty Client/DEBUG] [5zig/]: OUT| eu.the5zig.mod.chat.network.packets.PacketHeartbeat@1f3dc8f (5 bytes)
[20:54:33] [5zig Netty Client/DEBUG] [5zig/]: IN | eu.the5zig.mod.chat.network.packets.PacketHeartbeat@76239a51 (5 bytes)
[20:54:33] [5zig Netty Client/DEBUG] [5zig/]: OUT| eu.the5zig.mod.chat.network.packets.PacketHeartbeat@1c7be78f (5 bytes)
[20:54:38] [5zig Netty Client/DEBUG] [5zig/]: IN | eu.the5zig.mod.chat.network.packets.PacketHeartbeat@67565497 (5 bytes)
[20:54:38] [5zig Netty Client/DEBUG] [5zig/]: OUT| eu.the5zig.mod.chat.network.packets.PacketHeartbeat@785efb56 (5 bytes)
[20:54:43] [5zig Netty Client/DEBUG] [5zig/]: IN | eu.the5zig.mod.chat.network.packets.PacketHeartbeat@12c5071e (5 bytes)
[20:54:43] [5zig Netty Client/DEBUG] [5zig/]: OUT| eu.the5zig.mod.chat.network.packets.PacketHeartbeat@51c1cd56 (5 bytes)

The mod that 5zig is conflicting with (removing either of them allows the game to start as normal) is one that simply adds a confirmation to the disconnect button. It should not be causing this.