If an amphibious unit goes on foot does it lose its amphibious capability? I believe the answer is no.
Due to it being a flag, the unit retains its amphibious capability when On Foot.
I ran a test in Scheldt '44, and the amphibious infantry unit could both cross a river hexside and the Waal 1 hex river when On Foot.
Should it work like that though? On Foot means vehicles have been left behind...