After careful consideration, I've made the definitive choice to discontinue the use of the external JAR library, ProtocolLib, owing to its unreliable and faulty codebase. In its place, I've seamlessly integrated the PacketEvents API developed by @retrooper. This transition has effectively addressed all server-related issues and ensures smoother functionality.
For the latest version of PacketEvents, please refer to the following link: PacketEvents API Download Link