This thread is full of information !!

same issue reported here. And following posts.

I had mine replaced once as I posted in that thread and my replacement is doing the same thing as well. I clean mine frequently and it still happens. I called them about it a few months ago and they said they wouldn't service it for just that because it is still fine to use. Let me know if you have any luck and I'll press them again.

I don't know how much sleep is being lost to worry over health issues from possible ingestion of the non-stick coating under the group. BUT... at the very least, it is nothing like say making an omelette in a flaking pan. Because there is almost no way for debris to get into your body. What you are left with is below boiling water to leach "bad stuff" (if there is any), from the coating material. But water is exposed to the coating material whether it's flaking off or not. At this point I'm considering the health risk of a flaking group pad to be in the minimal category, simply because I cannot visualize a physical process that would make it otherwise. Certainly not in the same league as a flaking frying pan where flakes can directly enter the food you are eating, cooked with temperatures way above boiling, sometimes double. My thoughts.

Not to detract from general irritation that this is happening.

-Peter

That looks pretty nasty. Do we know what the coating is made of?

No way to know for sure, but it seems like some kind of non-stick coating like you might find on a kitchen pan. Fortunately, in espresso, there is no greater exposure to it whether it flakes or not.

-Peter

Peter, I make my own water - distilled and potassium carbonate. Because of that I don't use a water filter. Do you think I should?

No need for the Breville filters. Your water recipe is scale free. You are good to go!

-Peter

I would be in doubt only if it was the old water tank, because it does not have the metal mesh to prevent debris from entering the machine. In that case I would keep at least the base of the filter in place.

pictures here

True. When I had the older style tank, I used one of the old style bean bag filters. Not for the softening beads inside, but because the "bag" was made of white filter floss to trap any debris that might have gotten in the tank.

-Peter

I received a replacement. The machine is brand new. I removed the shower screen and the coating is still perfect. I will check for flacking every week or two.