[SOLVED] Why is workspace:Raycast() completely ignoring unions?

I am working on a weather system that works great; for everything except union operations. For some reason, the ray passes straight through all the unions, despite setting the collision fidelity to Precise, and all best efforts to fix any collision problems that may be caused by it.

(One of the unions is a block part that was unioned, and has 12 triangles, so it is not complexity)

Each emitter part is casting a ray directly below it with the following code:

local ignore = {}
for _,player in game.Players:GetChildren() do
	if player.Character then
		ignore[#ignore+1] = player.Character
	end
end

local raycastParams = RaycastParams.new()
raycastParams.FilterDescendantsInstances = ignore
raycastParams.FilterType = Enum.RaycastFilterType.Blacklist
raycastParams.IgnoreWater = false

local hit2 = workspace:Raycast(emitter.Position, Vector3.new(0,-5000,0), raycastParams)
if hit2 ~= nil then
	if hit2.Instance.Name == "Union" then
		print(hit2.Position)
	end
end
if hit2 ~= nil and hit2.Position.Y > -500 then
	local hit_pos = hit2.Position
	print(hit_pos, hit2.Instance)
end

The code returns the hit position and instance of the baseplate below the union, and completely ignores the union.

Relevant game if you want to see it in use: https://www.roblox.com/games/11262775141/Dynamic-Rain

Link to the model with the entire code found in the game: https://www.roblox.com/library/11461945331/Rain-Module

Found the problem after hours. Roblox should have this in their documentation, but raycasts do not detect unions past 2000 studs, despite it detecting parts and terrain up to 5000

Thus, as I was placing my rays at y=5000 to detect as much of the map as the raycast would allow, no unions were detected at all.

TLDR don't try and raycast over 2000 studs if you want to detect unions.