findPartOnRay -- Why is it detecting itself? Do rays work in spheres?

I have many sphere instances. They all shoot a ray and use findPartOnRay to see what's near them. The problem is that the ray start at the center of the sphere but can't make it out. It's like the sphere has thick skin.

https://i.imgur.com/LUOe1dd.jpg

If I use ignoreDescendantsInstance, the ray can pass through and hit other objects in the world as it should. But that solution isn't optimal because I have many spheres shooting rays all with different names.

--Sphere properties
citizenID = citizenID + 1
local evo = Instance.new("Part", workspace)
evo.Name = "citizen"..citizenID
PhysicsService:SetPartCollisionGroup(evo, evoCollisionGroup)
evo.CFrame = CFrame.new(9, 5, 5)
evo.Shape = Enum.PartType.Ball
evo.BrickColor = BrickColor.new("Bright green")
evo.FormFactor = "Custom"
evo.Material = "Neon"
evo.Transparency = 0.25
evo.Anchored = true
evo.Locked = false
evo.CanCollide = true

--Ray stuff
local target = citizen.CFrame.p + Vector3.new(0, 15, 0) 
local ray = Ray.new(citizen.CFrame.p, (target - citizen.CFrame.p).unit * 50)
local seen, hitposition = workspace:FindPartOnRay(ray, nil, false, true)

Also, if I change the part to a block instead of a sphere, and use the exact same code, everything works. Do rays not work in spheres or something?