It certainly could be although I don’t recall the water being soapy at all but you are right in that even a little might make a big difference. I know that I have been in pools, lakes, and the ocean for similar periods of time without the same problem. As a matter of fact, most of us have experienced finger shriveling after only an hour or so in a soapy tub so that might be the key. My experience was like that x10. Maybe it was the soap.