glibc 2.27 was initially released with userspace emulation for copy_file_range, but the kernel has evolved in a different direction, so the emulation had to be removed in glibc 2.30. The removal was backported into 2.27, 2.28, 2.29 and most distribution glibc versions.

Found through code inspection, no failure is known. For the issue to be visible, glibc 2.27 or later (with the backport) would have to be used on an older kernel with no or partial copy_file_range support.