12V 19A LT8390 CCT output keep going into hiccup mode when a load is applied.

Hi All,

My circuit use a LT8390 to  convert 24V 10A supply to 12V 19A(max).  It suffers from the following issue:

1.  If a load > 0.5A is add the output goes into oscillation 12V to 11.2 

2.  PGOOD output seems to reset and power in a the sequence described in the data sheet as the "Hiccup Mode"


Please does anyone have any suggest as to why my circuit goes into this Hiccup mode as soon as a load is applied