Oddness regarding supplying sneaky troops

[Saber Cherry]

I'm talking about Dominions 1, and not my stealth units, but suspected enemy stealth units. I just noticed that sometimes, the supply level would temporarily drop in a province I owned, when (I think) all the scales stayed the same. The only reason I can imagine for this is a stealth army passing through, but I can't confirm this to be the case, and Nagot Gick Fel thinks stealthy troops don't eat while sneaking.