rsync stalls in MacOS 15 Sequoia

I have several directories with thousands of files that I synchronize to my Mac using rsync. With Sequoia Apple has switched to a new rsync -- I can tell because the verbose output has changed. But this rsync has a bug that shows up on both Intel and Apple Silicon. This has been persistent across all versions of MacOS 15 to date, and on two different Macs.

In this case, I am transferring a large number of files, all of which are relatively small.

I execute the following command:

rsync -av [source] [destination]

The source is on a remote server.

The command will stall after transferring somewhere between 800 and about 1300 files. I did some testing using tee directed to wc to make counts. It always stalls between completing the download of one file and starting the next. I have experienced this hundreds of times now, and have never had an incomplete file. Prior to the Sequoia upgrade, a single rsync command would get all files (or all newer files) in the source with a single command. Now, it takes about 15-25 executions to get all the files (about 27,000 files), and by the time I get them all, it is time to start again because they are updated regularly. The transfer will stall forever (until killed by control-C), so it cannot be done in the background -- a human must be present to kill and restart.

Removing the -v command does not change things, except that you can't tell that the process has stalled other than by looking at the clock. The -v at least lets you see that the output has stopped.

This really needs to be fixed. A process that I used to be able to have my machine do automatically now requires extensive human interaction to complete.