The timing is just so close to the planned start date. Sometimes employers offer a later start if the places are full before applicants complete assessments. They do not. One reasonable explanation I can think of is that their budget got cut recently so they wouldn't have as many new joiners as before. Didn't see many unsuccessful applications lasting this long in the past years. Along with recent scandals, the way they dealt with applicants made their management untrustworthy.
Anyway heads up guys, there will be other opportunities and perhaps better than this one haha.