I have Ford Focus 1.0 Ecoboost 2015 which has a coolant leak. I took it to a garage 2 months ago where they suspected a leak through the heater matrix... Given the circumstances you describe a fault ...

2009 is the year when the first EcoBoost powerplant rolled off the production line. More than a decade later, Ford still hasn’t fixed the issue affecting four-cylinder engines marketed under this name ...