I recommended the steam boiler had a 70% approx fill in the original design, and as the Gicar boxes overfill slightly on an autofill (for technical reasons, I wont go into here)
1.7 litre sounds OK. I assume you switched the machine off before draining it?
Certainly the machine is not running short of water exposing the autofill probe tip and then switching off the heating elements….also if it was doing that the pump would run. With the amount of water in that you have.,..it’s a massive steam battery.
Keep and eye on it, as the only other possibility might be some, strange wierd fault in the Gicar box I am simply guessing here, spitballin if you like.. Possibly theres a sticky mechanical relay inside..although looking at the inside of one, the boiler elements are controlled by SSRs as the Minima control box is significantly larger than the normal control box, as it has the SSRs and the PID chip inside ( the thing with buttons on the outside is simply a display, no real electronics)