Ahhh ok! Well then that is simple. It’s likely the water is having a slower effect on the breakdown of the foam. Especially if you say used tap or warm water which is going to be closer in temperature to the foam. Meaning that the temperature shift is not as dramatic and prevents the foam from breaking down as quickly. If you’re looking for things to do I would say for sure as you’ve done here the water would definitely help this (doesn’t need to be a lot either. Even like 1/4 inch or 1/2 inch of water might suffice). Additionally anything to help minimize that temperature shift would likewise help slow the breakdown of the foam. So possibly consider doing light, or no ice with it when making it (as it seems like you have some in the picture). Other than that there’s not too much you can do. It’s kind of part of the trouble with foam on iced drinks. It just doesn’t bode as well as warm drinks because the temperature shift is going to cause the micro foam to break down MUCH faster than in that of a hot drink. Hopefully this helps though! Definitely see what others say though, am sure there’s some ideas online about how best to keep foam intact on iced drinks.