Arch Linux

Not sure if this affects the issue, but the Samba shares I've tested with are mounted with user authentication (username and password)

I'm facing the same issue, pretty sure this forum thread is related as well:
> https://bbs.archlinux.org/viewtopic.php?id=279992

I did a quick strace, hope this helps:
❯ strace cp -R ~/test-folder/ .
execve("/usr/bin/cp", ["cp", "-R", "/home/tile/test-folder/", "."], 0x7ffe4b7d89e8 /* 59 vars */) = 0
brk(NULL) = 0x5637a1975000
arch_prctl(0x3001 /* ARCH_??? */, 0x7ffdf20179b0) = -1 EINVAL (Invalid argument)
mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f7744c0c000
access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
newfstatat(3, "", {st_mode=S_IFREG|0644, st_size=186223, ...}, AT_EMPTY_PATH) = 0
mmap(NULL, 186223, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f7744bde000
close(3) = 0
openat(AT_FDCWD, "/usr/lib/libacl.so.1", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0 \0\0\0\0\0\0"..., 832) = 832
newfstatat(3, "", {st_mode=S_IFREG|0755, st_size=34680, ...}, AT_EMPTY_PATH) = 0
mmap(NULL, 36896, PROT_READ, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f7744bd4000
mprotect(0x7f7744bd6000, 24576, PROT_NONE) = 0
mmap(0x7f7744bd6000, 16384, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x2000) = 0x7f7744bd6000
mmap(0x7f7744bda000, 4096, PROT_READ, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x6000) = 0x7f7744bda000
mmap(0x7f7744bdc000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x7000) = 0x7f7744bdc000
close(3) = 0
openat(AT_FDCWD, "/usr/lib/libattr.so.1", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0 \0\0\0\0\0\0"..., 832) = 832
newfstatat(3, "", {st_mode=S_IFREG|0755, st_size=26488, ...}, AT_EMPTY_PATH) = 0
mmap(NULL, 28696, PROT_READ, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f7744bcc000
mmap(0x7f7744bce000, 12288, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x2000) = 0x7f7744bce000
mmap(0x7f7744bd1000, 4096, PROT_READ, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x5000) = 0x7f7744bd1000
mmap(0x7f7744bd2000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x5000) = 0x7f7744bd2000
close(3) = 0
openat(AT_FDCWD, "/usr/lib/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P4\2\0\0\0\0\0"..., 832) = 832
pread64(3, "\6\0\0\0\4\0\0\0@\0\0\0\0\0\0\0@\0\0\0\0\0\0\0@\0\0\0\0\0\0\0"..., 784, 64) = 784
newfstatat(3, "", {st_mode=S_IFREG|0755, st_size=1953472, ...}, AT_EMPTY_PATH) = 0
pread64(3, "\6\0\0\0\4\0\0\0@\0\0\0\0\0\0\0@\0\0\0\0\0\0\0@\0\0\0\0\0\0\0"..., 784, 64) = 784
mmap(NULL, 1994384, PROT_READ, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7f77449e5000
mmap(0x7f7744a07000, 1421312, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x22000) = 0x7f7744a07000
mmap(0x7f7744b62000, 356352, PROT_READ, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x17d000) = 0x7f7744b62000
mmap(0x7f7744bb9000, 24576, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x1d4000) = 0x7f7744bb9000
mmap(0x7f7744bbf000, 52880, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7f7744bbf000
close(3) = 0
mmap(NULL, 12288, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f77449e2000
arch_prctl(ARCH_SET_FS, 0x7f77449e2740) = 0
set_tid_address(0x7f77449e2a10) = 15717
set_robust_list(0x7f77449e2a20, 24) = 0
rseq(0x7f77449e3060, 0x20, 0, 0x53053053) = 0
mprotect(0x7f7744bb9000, 16384, PROT_READ) = 0
mprotect(0x7f7744bd2000, 4096, PROT_READ) = 0
mprotect(0x7f7744bdc000, 4096, PROT_READ) = 0
mprotect(0x5637a0040000, 4096, PROT_READ) = 0
mprotect(0x7f7744c3f000, 8192, PROT_READ) = 0
prlimit64(0, RLIMIT_STACK, NULL, {rlim_cur=8192*1024, rlim_max=RLIM64_INFINITY}) = 0
munmap(0x7f7744bde000, 186223) = 0
getrandom("\xcd\x8e\x5e\x96\xe9\xf3\x08\x31", 8, GRND_NONBLOCK) = 8
brk(NULL) = 0x5637a1975000
brk(0x5637a1996000) = 0x5637a1996000
openat(AT_FDCWD, "/usr/lib/locale/locale-archive", O_RDONLY|O_CLOEXEC) = 3
newfstatat(3, "", {st_mode=S_IFREG|0644, st_size=3407104, ...}, AT_EMPTY_PATH) = 0
mmap(NULL, 3407104, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f77446a2000
close(3) = 0
geteuid() = 1000
newfstatat(AT_FDCWD, "/home/tile/test-folder/", {st_mode=S_IFDIR|0755, st_size=0, ...}, AT_SYMLINK_NOFOLLOW) = 0
newfstatat(AT_FDCWD, "test-folder", 0x7ffdf20174e0, AT_SYMLINK_NOFOLLOW) = -1 EACCES (Permission denied)
openat(AT_FDCWD, "/usr/share/locale/locale.alias", O_RDONLY|O_CLOEXEC) = 3
newfstatat(3, "", {st_mode=S_IFREG|0644, st_size=2998, ...}, AT_EMPTY_PATH) = 0
read(3, "# Locale name alias data base.\n#"..., 4096) = 2998
read(3, "", 4096) = 0
close(3) = 0
openat(AT_FDCWD, "/usr/share/locale/en_US.UTF-8/LC_MESSAGES/coreutils.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/usr/share/locale/en_US.utf8/LC_MESSAGES/coreutils.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/usr/share/locale/en_US/LC_MESSAGES/coreutils.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/usr/share/locale/en.UTF-8/LC_MESSAGES/coreutils.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/usr/share/locale/en.utf8/LC_MESSAGES/coreutils.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/usr/share/locale/en/LC_MESSAGES/coreutils.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
write(2, "cp: ", 4cp: ) = 4
write(2, "cannot stat './test-folder'", 27cannot stat './test-folder') = 27
openat(AT_FDCWD, "/usr/share/locale/en_US.UTF-8/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/usr/share/locale/en_US.utf8/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/usr/share/locale/en_US/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/usr/share/locale/en.UTF-8/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/usr/share/locale/en.utf8/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
openat(AT_FDCWD, "/usr/share/locale/en/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory)
write(2, ": Permission denied", 19: Permission denied) = 19
write(2, "\n", 1
) = 1
lseek(0, 0, SEEK_CUR) = -1 ESPIPE (Illegal seek)
close(0) = 0
close(1) = 0
close(2) = 0
exit_group(1) = ?
+++ exited with 1 +++

This looks like an upstream problem so it won't get fixed unless someone reports it to them. Have you done so yet?

Dupe  FS#76158  (patch available)

https://bugzilla.samba.org/show_bug.cgi?id=15195