Меседж US-provided weapons do not end up in Ukraine. Russian media disseminate such reports with reference to an interview with Acting Inspector General of the US Department of Defense Sean O'Donnell to the American edition of Bloomberg
Allegedly, O'Donnell admitted that neither the United States nor Ukraine can say with 100% certainty where the weapons they sent to Ukraine end up. It is not true.
As the fact-checker of the Georgian project Myth Detector writes, Russian propaganda manipulatively quotes only those parts of the interview that talk about possible violations, and do not mention measures of information about the established weapons control mechanisms. O'Donnell did say that the Pentagon would consider possible cases of weapons entering the “black market”. But so far we are talking only about an assumption, and not about a fait accompli of violations. The article also explains that the Pentagon has detailed arms monitoring mechanisms, which also include the US European Command and a new defense attaché office in Kyiv. As noted in the Bloomberg article, O'Donnell's team was in Germany in June and discussed this issue with representatives of the European Command.
Russian propaganda systematically uses quotes taken out of context to advance their narratives. Previously, propagandists spread messages that the United States and Germany do not trust the Ukrainian authorities.