In other countries like East Timor or Ecuador that also minted their own "USD cent coins" this not happen ¿Why? 
This have not sense 
I can think of three possible reasons:
Least likely: it is already known that issues of bond notes and coins surpass the value of the bonds, so they are not fully covered.
Maybe, maybe not: the story is untrue.
Most likely: people do not trust that the issues of bond notes and coins are or will be equal or less than the value of the bonds: they believe the coins and notes are not now or will not in the future be fully covered.
Peter