Q: Forget a network on iPhone and it comes back later

Tell me if this has happened to you.

You go to the supermarket, and there's an open wifi hotspot there that doesn't require a key, but you have no need for that wifi right now.  my iPhone automatically connects, making it hard to receive messages because this wifi ***** or doesn't have proper connectivity or has a sign on page you don't want to fool with.  So I just want to forget it.  So I do, go into settings > wifi, find the network, hit the i and hit "forget network."  It's forgotten... for now.

I come back some other time, and it reconnects to this network!!  I then have to forget it all over again!

I have the setting for "ask to join networks" turned off.  Per the note below the setting it says "Known networks will be joined automatically, if no known networks are available, you will have to manually select a network."  With this on, a popup is constantly coming up asking to join networks getting in my way.  I want the phone to automatically join my home network, work network, and a few other networks like family houses that have wifi.  I do not want to connect to this **** supermarket network, ever.  the note imples to me that I have to go into network settings and select a network to join it, and then if it's known it will connect automatically, whereas with this on it always asks to connect, always.

Something I noticed is that when I go to my wifi settings on my Mac at home and look at saved networks, it seems to remember every network I have ever joined including this supermarket wifi.  I clear out this list, and at some point it all comes back!  Is icloud remembering all my networks and not allowing me to blow them away?

I've reset my network preferences to see if this helps and the issue eventually comes back.  I've not tried switching to a new icloud ID, which really isn't an option at this time.

Thoughts on how to correct this situation?