Is this an occasional bug or is it always like this? You said it fixes itself after a reload.
You could try calling
MultiActionBar_HideAllGrids() or, if that doesn't do it, loop through every action button and do something like..
Lua Code:
local function ActuallyHideGrid(barName)
for i=1, NUM_MULTIBAR_BUTTONS do
local button = _G[barName.."Button"..i]
button:SetAttribute("showgrid",0)
if not HasAction(button.action) then
button:Hide()
end
end
end
ActuallyHideGrid("MultiBarBottomLeft")
ActuallyHideGrid("MultiBarBottomRight")
ActuallyHideGrid("MultiBarRight")
ActuallyHideGrid("MultiBarLeft")