All these Eco boost engines run hotter than the older 4 cylinder non turbo Ford Engine, I have never seen an eco boost Fiesta WITHOUT the cooling fan running. So keep a close eye on the coolant level and look carefully for any leaks both inside the engine compartment and on the ground after parking ( however expect condensation from the air conditioning which often forms a small puddle).

If you suspect the bubbles in the Coolant tank are not normal you could ask a garage to test the coolant I believe they can detect a chemical in the coolant which might indicate a leak in the cylinder head gasket.

If you bought the car from a car dealer take it back there as soon as practicable, also you could get the opinion of an independant qualified mechanic who is familier with this engine.