This is… strange. WorldPartionHlodUtilities is one of the plugins that’s enabled by default by the engine I think. One that’s not specifically enabled by you (not defined in .uproject file). I just check one of my approved submissions (for engine version 5.1.1) and that plugin is enabled, alongside bunch of others:
Maybe it somehow got enabled in your .uproject file? That one I know for sure that needs to be ‘clean’. Here’s mine for that 5.1.1 project:
{
"FileVersion": 3,
"EngineAssociation": "5.1",
"Category": "",
"Description": "",
"Plugins": [
{
"Name": "ModelingToolsEditorMode",
"Enabled": false,
"TargetAllowList": [
"Editor"
]
}
]
}