I would guess that perhaps your second machine is running a different version of Visio or perhaps has different options set.
Does the page re-organise consistently in the same way if you run this macro?
Code:
Sub ArrangeMyOrg()
Application.AutoLayout = True
With ActivePage
.PageSheet.CellsSRC(visSectionObject, visRowPageLayout, visPLOResizePage).FormulaForceU = "TRUE"
.PageSheet.CellsSRC(visSectionObject, visRowPageLayout, visPLOAvenueSizeX).FormulaForceU = "7.5 mm"
.PageSheet.CellsSRC(visSectionObject, visRowPageLayout, visPLOLineRouteExt).FormulaForceU = "1"
.Layout
End With
End Sub