I had this issue, i tried work around it, but it just won't work, i've tried to re-size WorldMapFrame, WorldMapFrame.ScrollContainer.Child etc, no results.
For now i've just skinned it and repositioned it and this works.
Lua Code:
function WorldMap:SkinMap()
local WorldMapHolder = CreateFrame("Frame", nil, UIParent)
WorldMapHolder:Size(WorldMapFrame:GetWidth(), WorldMapFrame:GetHeight())
WorldMapHolder:Point("CENTER", UIParent, 0, 122)
WorldMapFrame:SetParent(WorldMapHolder)
WorldMapFrame:ClearAllPoints()
WorldMapFrame:Point("CENTER", WorldMapHolder, 0, 0)
hooksecurefunc(WorldMapFrame, "SetPoint", function(_,_, Parent)
if (Parent ~= WorldMapHolder) then
WorldMapFrame:ClearAllPoints()
WorldMapFrame:Point("TOP", WorldMapHolder, 0, 0)
end
end)
end