Add known issue.

Author: lewmilburn

Writerside/LewMCWiki.tree

@@ -20,6 +20,7 @@
             <toc-element topic="ES-Teams.md"/>
             <toc-element topic="ES-Kits.md"/>
             <toc-element topic="ES-MOTD.md"/>
+            <toc-element topic="ES-Troubleshooting.md"/>
         </toc-element>
         <toc-element topic="Kryptonite.md">
             <toc-element topic="KR-Changelogs.md"/>

Writerside/topics/ES-Troubleshooting.md

@@ -0,0 +1,7 @@
+# Troubleshooting
+
+## Invalid move player packet received
+This error can sometime occur when a non-vanilla loaded world is set as the main-world if always-spawn is also enabled.
+We recommend setting the main-world to a vanilla loaded world (the world set in server.properties) if you also use always-spawn.
+
+If this is not causing the issue please [open an issue](https://github.com/lewmc/essence/issues).