My eye is caught by the "0.8V" minimum on the output, It may not like a hard short.
Equally full open to a sudden short will be the hardest test you can do on a PSU, until the control loop responds it can have far far more than your 5A set point, this can pop transistors if its not well built
The fact it says not to short the output for long would back up that 0.8V minimum, it may be that with a hard short it cannot regulate it.