That sounds like:

Most likely, the thermostat has built up a lot of carbon on its contacts and now (even when contacts are closed) is a noticeable resistance in the circuit and is generating heat and tripping over its own generated heat. Nice easy and affordable fix, replace the thermostat.

Less likely. The gauge and pressostat could both be suffering from calcium arthritis, p-stat not switching because it's reading too low, gauge not reporting that it's really over pressure because it's too stiff. This is far less likely than the first option, but when the gauge is at 0.8 Bar and you open the steam valve, does it look like the boiler is over pressure or actually kinda low?

(Note: I haven't touched a Pavoni in 10 years. Ignore me if they no longer work that way with the stupid P-Stat tube UNDER the calcium build-up, etc).

You make a good point! It seemed to coincide with a descaling. Quite possibly got crud into the p-stat pipe...
(With the p-stat removed and the lid off the boiler, that pipe can be flushed with just water, or more descaler, up to you... Over a sink)