While it doesn't sound like this is a new thing with the Trump Administration, and there's certainly no love lost (for a variety of reason) between the US government and Cambodia's.
But … yeah, some food "loans" from the Viet Nam era that Cambodia incurred (and which have been accumulating interest since then) are probably more than paid for by the continue unearthing of unexploded ordinance the Cambodians are still digging up around their countryside after massive secret bombing by the US in that nation against Viet Cong supply lines that passed through the nation.
I have no doubt, though, even if other Administrations have raised the issue in the past, that the Trumpists will manage to make the situation worse. Unless they sent Henry Kissinger over personally to collect on the debt. I think that might just satisfy them … if we didn't mind what happened to him there.
Fury in Cambodia as US asks to be paid back hundreds of millions in war debts
Half a century after United States B-52 bombers dropped more than 500,000 tons of explosives on Cambodia’s countryside Washington wants the country to repay a US$500 million war debt.
Yes, please
extraditesend Kissinger. There's a plan I get behind.