leaving water province after removing water breathing item

[Incabulos]

I did a few tests and as far as I can tell you can wear a water breathing item, enter a water province and the next turn remove that water breathing item and leave the province (the same turn you remove the item) and the unit doesn't drown.

I was testing this with flying troops (caelum mages) is there any reason the same wouldn't be true for landbound commanders?

Also is this WAD?