Keep in mind that the majority of these Jabiru engines are being operated privately on the RAA or other equivalent international registers. Any failures that have occured in the past won't necessarily be known to us.
Additionally, the Jabiru 160 hasn't been used extensively in this environment before. The organisation concerned does a lot of hours with quick breaks between flights and often a 1-2km taxi to/from the runway. In good weather, it was a rare sight to see all their Jabirus on the ground at one time and this type of heavy use and longer taxi times is not what the aeroplanes were designed for. The reports of 45 minute taxis above are probably fairly exaggerated, but even a difference of 10 minutes ground time over 6 flights a day, quickly adds up to a lot of hours spent with minimal engine cooling over a period of months.
It is important to note that this is not the result of mishandling by the pilots/instructors - quite the opposite. The aeroplanes are used for ab initio flight training. Rolling runups, rushed checklists and fast taxiing would be totally unsafe. If that is what's required to avoid engine problems, the aeroplane needs to be redesigned before it is used again in that environment.
Interestingly, that is exactly what's happening.
As for taking off with gauges indicating over the red-line, that really doesn't sound very likely. I know enough about the organisation to know their pilots are fairly intolerant of unserviceabilities, and out of unfamiliarity with the Jabirus, were reluctant to fly them even when the gauges were green, let alone with any indication of a problem. Sounds like the 'alleged rumour' has grown from a temperature problem (fact) to pilots taking off with known unserviceabilities (fiction).
In the spirit of talking about the facts, does anybody know if the two CHT probes on these engines are on the back cylinders or the front?