Why Are the Long-term US Treasury Yields Falling?

First, let me answer the question in the title: I do not know because, according to conventional theories, when the realised and expected inflation rates are as high as they are in the United States (US), the long-term US Treasury yields should go up.

Although the realised and expected inflation rates have been going up since April 2021, the long-term US Treasury yields, however, have not been rising. Not only that, but they have started falling. We see this from Figure 1 (p 11), which is the daily graph of the 10-year US Treasury yield from 2 January 2020 to 9 July 2021.