@Palladini what exactly did the mechanic do? Was this Ford dealership or independent? Does this happen only a certain times, such as when it rains, or just occasionally? If when it rains, after it sits outside or when driving? If sitting outside, is car parked at an angle when it happens? (Some cars leak when parked front facing up, but not when rear facing up.)
Believe you have a 2015, possible causes on passenger side include a leaking heater core, clogged AC drain and external water leak around door hinge. Coolant has smell, clogged AC drain, water smells musty. If external leak, dealer can fix permanently and Ford pays.