I have continued using the Microcimbali with the anode, and the sediment kept coming out of the boiler. I started to reflect on a comment on this subject, that without fully understanding the galvanic circuit by adding magnesium into the environment may make things worse!

So this week I ran it without the magnesium anode.
The result was no better.

The anode is showing signs of corrosion, so it is going back in. It could just be the thermal expansion and contraction cycle through use that is loosening and sheding the corrosion layer that was in the boiler?
Ultimately a replacement stainless steel boiler appears to be the healthiest option.