I am certainly not a bond or mortgage expert, but I have been researching the same issues you ask in your original post. Here’s what I’ve learned.

Over the short term, many different things effect mortgage rates, and I’ve observed with each recent Fed short term rate cut, a temporary spike in 30 year fixed mortgage rates. So for a brief period, you can see mortgage rates move opposite of the short term, or Fed rates.

But I recently did a spreadhseet tracking the 30 year fixed average vs the Fed Funds rate since 1990, and found they track very closely over a long term. The short term Fed rates move very steadily, with changes only every quarter or six months, while mortgages had more volatility, changing daily and weekly. This past week is an example of that volatility, where morgages jumped big time after the Fed cut its rates by a total of 1.25%.

But over a long term, when the Fed lowers its rates, mortgages eventually fall as well.