Those are 30 year old documents. Much like everything else the patriot technology has advanced a lot since then.
https://en.wikipedia.org/wiki/2018_Riyadh_missile_strike
"However, according to Jeffrey Lewis, director of the East Asia Nonproliferation Program at CNS, the Saudis failed to intercept the missiles following a malfunction of the MIM-104 Patriot system.[3] One video appeared to show a Patriot missile launch on Sunday night go rapidly wrong, with the missile changing course midair, crashing into a neighborhood in Riyadh and exploding. Another appeared to detonate shortly after being launched in the Saudi capital. " Pretty much the same failure mode as 30 years ago I would say, so maybe those ancient documents are still relevant today.
That's 10% of all patriots manufactured in 1 year.
The Russians also arrested the scientists who helped develop the Kinzhal and charged them with treason due to the apparent failure during this attack.[3] Not something you usually do if your weapon system is successful.
[1] https://apnews.com/article/russia-ukraine-war-patriot-kinzha... [2]https://www.bloomberg.com/news/articles/2023-05-06/ukraine-s... [3] https://www.nbcnews.com/news/world/russia-hypersonic-missile...
Arrests happened previously, and then 3 additional individuals were arrested after the most recent attack.
In total, there are currently 16 individuals related to the program who have been arrested. 3 of them are facing life in prison for treason.
The Ukrainian air force itself even denied that any Kinzhals had been shot down:
https://news.yahoo.com/ukrainian-air-force-denies-reports-13...
> On May 4, 2023, Ukraine used a U.S.-supplied Patriot battery to down a Russian Kinzhal missile, which Russian President Vladimir Putin had announced in 2018 was a “hypersonic” weapon that could overcome all existing air defense systems. Russia’s state news agency tried to maintain this claim by arguing that the shootdown was a fake report. Yet just 12 days afterward, Ukraine shot down six Kinzhals [1] that Russia fired in an assault on Kyiv. Both shootdowns have been verified by U.S. government sources.[2]
[1] https://www.nytimes.com/2023/05/16/world/europe/ukraine-russ... [2] https://www.brookings.edu/blog/order-from-chaos/2023/05/23/u...
Additionally, an open letter from the Russian scientific community was published strongly denouncing these arrests this month. The "media" isn't being misleading - they are reporting the events as they are happening.
>Ukraine Says
Surely Ukraine, being in the middle of a war, would have no incentive to lie for propaganda purposes. As the other commenter pointed out they were arrested way earlier and the reason was because they sold secrets to China not because of any failure of the project.
The US has a variable capacity for Patriot missile manufacturing but its baseline far exceeds the 300 missiles per year that you quoted.
That said, it's not necessarily due to failure to intercept that this happened - we have video of 30 interceptors being launched in rapid succession, and it's likely all 32 interceptors in the battery had been launched and expended when the final strike and explosion happened. So it's more of a successful saturation attack than an interception failure.