It did happen under Trump. Trump was in office when millions of dollars in US weapons were handed over to the Afghan army. Trump negotiated the US withdrawal from Afghanistan and there was never any intent to reclaim those weapons. The Afghan army was expected to use them to stop the Taliban from seizing control. Its not entirely Trumps fault of course. That nation building nonsense was the policy of multiple administrations and Trump did set in motion the ending. But those weapons ending up with the Taliban was destined the moment we sent them to Afghanistan.