I have tested my show, and it is displaying my shopping list. If you log into the Alexa app on your phone, can you see the shopping list in there?

Yes, it shows my shopping list in the app. On my Echo Show it correctly responds to "Alexa, add parmesan to my shopping list".

It shows the shopping list in a widget (if you swipe from the right side). But it won't show/let me edit the shopping list on the screen when I say "Alexa, show my shopping list" 

It just says "Sorry, I can't list your shopping list at the moment. Try again later."

I have tried mine and it lets me view the list , edit or delete each item.  Mine is  Show 5 2nd gen. I think I maybe connected to a US Amazon account as I setup my Alexa account before it was available in NZ and had one of the first Amazon Echoes.

Thanks. I tested on both Echo 8 and Echo 10 - both a US account. Both say they can't access my shopping list. I will try creating a new list after the conference call I am in now.

Just started last week, and it's happening on both Echo Show I have here - one was off for a while (too many Echos around the house).

I remember getting a notification that scanning barcodes to add to shopping list was  going away with the latest update.

Just tried mine with a US account and it showed the shopping list fine, and I scanned a can of rootbeer to it and it added it fine. If they take away the scanning to the list I will be pissed because I use it a lot.

To rule out my network, router, security I connected one of the Amazon Echo to a 4G router, completely unmanaged. It still won't show/read my shopping list.

That sounds like some weird bug in their code for that to happen.

Yeah, it's working for me.