I haven't experienced any problems directly related to tabs either. But about the time I learned of this, SubRosa of Amazon: Total War was having some problems implementing factionwide bonuses to mimic wonders. After I told her about this, and she replaced the tabs with spaces, the coding worked. I figure that it isn't that hard, depending on how much you care about exact spacing, to replace all tabs with spaces and if it fixes that one rare problem it's worth it.