There is nothing new about a steady trickle of people leaving CX or KA after problems during induction, upgrade or even conversion training.
It is similar in most Airlines.
The rumors generally paint a picture of a saint, heartlessly chopped because of deficiencies in the training system. However, the reality is usually far more complicated.
A good example would perhaps be experienced based pilots converting from one Boeing type to another. Most people will reach line check standard within the syllabus number of sectors. But a handful of people will not, and a very few will not reach the standard even after a further 10-20 or even 30 extra sectors.