I opened a new baseplate, placed my 30 unionpart gun and opened a simple test server/player.
The test player always gets disconnected because of a particular high data CSG part.
This error occurs when multiple excessive union operations are used and the union part approaches the 2500k poly limit.
Something is gonna have to be done about those gigantic child data by hopefully resolving more union solvable issues so we can perform all union operations in one step.
Test Player
Test Server