Regardless of what the video shows, the U.S. admitted this happened at least once and called it a mistake:
The Pentagon admitted on Wednesday that one of the airdrops of weapons
intended for Kurds in the besieged Syrian town of Kobani almost
certainly ended up in the hands of the Islamic State (Isis) fighters.
Alleged eyewitnesses say they are sure, U.S. calls it ridiculous:
“It is not in doubt,” said Mustafa Saadi, who says his friend saw U.S.
helicopters delivering bottled water to Islamic State positions. He is
a commander in one of the Shiite militias that last month helped push
the militants out of the oil refinery near Baiji in northern Iraq
alongside the Iraqi army.
The Islamic State is “almost finished,” he said. “They are weak. If
only America would stop supporting them, we could defeat them in
U.S. military officials say the charges are too far-fetched to merit a
response. “It’s beyond ridiculous,” said Col. Steve Warren, the
military’s Baghdad-based spokesman. “There’s clearly no one in the
West who buys it, but unfortunately, this is something that a segment
of the Iraqi population believes.”
[...] On the streets of Baghdad, most Iraqis see no other explanation.
“The image of the U.S. was damaged in the region, so they created
Daesh in order to fight them and restore their image,” said Mohammed
Abdul Khaleq, a journalist for a local TV station who was drinking
coffee in a cafe favored by writers, most of whom said they agreed.
Basically, Iraqis are dead certain that this video shows purposeful aid to ISIS, and America says that's impossible, although their air drops have been received by ISIS in the past.
I was unable to find any American explanation of who this particular air drop was allegedly intended for, even though the Washington Post surely asked and the National Review could have pulled strings as well.