Christian Horner has opened up on the complaints that Max Verstappen has raised at Red Bull this year as he admits the Formula 1 team have fallen into ‘troubled waters’. The Milton Keynes outfit were an almost all-conquering force last season as Red Bull won 21 of the 22 Grand Prix. Verstappen even gifted Red Bull 19 of their victories en route to sealing his third consecutive drivers’ title. But their domination has diminished somewhat this term. Verstappen burst out of the gates to win four of the first five Grand Prix plus the F1 Sprint at the Chinese GP. The 26-year-old possibly only faile…