Reproducible error "[sender] write error: Broken pipe (32)" when copying into the mounted FAT disk

[yurivict]

I am copying several multi-gigabyte multimedia files from the FreeBSD disk to the mounted slow FAT (msdosfs) disk.
All files happen to have the "wheel" group, while FAT doesn't support groups.

'rsync -rav' first complains about failing chgrp, but then it prints this for one of the large files:

rsync error: error in file IO (code 11) at receiver.c(380) [receiver=3.3.0]
rsync: [sender] write error: Broken pipe (32)

Either chgrp failures cause this failure, or slowness of the disk causes it.

Version: 3.4.1
FreeBSD 14.2