chat bubbles clamping to top, :IsClampedToScreen() returns false

PratBubbles.lua

function module:IterateChatBubbles(funcToCall)
  for i = 1, WorldFrame:GetNumChildren() do
    local v = select(i, WorldFrame:GetChildren())
    local b = v.isChatBubble == nil and v:GetBackdrop()
    if v.isChatBubble ~= false and b and b.bgFile == "Interface\\Tooltips\\ChatBubble-Background" then
      v.isChatBubble = true
      print("A", v, v:GetDebugName(), v:IsClampedToScreen())
      for i = 1, v:GetNumRegions() do
        local frame = v
        local v = select(i, v:GetRegions())
        if v.IsClampedToScreen then
          print("B", v, v:GetDebugName(), v:IsClampedToScreen())
        end
        if v:GetObjectType() == "FontString" then
          local fontstring = v
          if type(funcToCall) == "function" then
            funcToCall(frame, fontstring)
          else
            self[funcToCall](self, frame, fontstring)
          end
        end
      end
    else
      v.isChatBubble = false
    end
  end
end