Fuselage condensation occurs in all aircraft. Passive means are the standard fitted on aircraft to prevent moisture issues. But in many situations those no longer are sufficient. In the past 20 years, airlines configure more seats (seat-densification) and operate with higher load-factors, causing water accumulation in the fuselage / structures. In addition, flights are scheduled with shorter turn-around and increased operational lenght. This result in more total flight hours per year (i.e. less drainage hours on ground).
A brand new aircraft quickly adds weight due to moisture build-up during the first year of operations. In many cases this occurs without direct signs of moisture accumulation.