The something that is wrong is that the UK ACO Gliders are not airworthy. The reason for that is because the UK Military Air Regulator is dysfunctional. The reason for that is the attack on UK Military Air Safety by VSOs in Haddon-Cave's "Golden Period" dealt it a fatal blow (try running a system that requires continuous review and audit given 28% cuts per annum for in excess of three years and VSO orders to suborn the regs. It doesn't work!).
The only ray of light in this gloomy scenario is that the fleet was grounded before someone died. Other fleets haven't been so lucky, there have been 70 deaths in airworthiness related UK military fatal air accidents itemised in this forum. The latest being Sean Cunningham's death at Scampton in 2014.