Memory Dumps on self run servers 1.15 - 1.15.1 (No Mods)

When loading own server (downloaded from Minecraft website, with no mods) the server had repeated rises in RAM usage and then dumps back to no RAM again.

The server is running with Max 4GB of RAM, with Java 64bit.

This only occurs when someone has joined the server from either an external network or internal network. If no players have joined the server the RAM will stay level.