This is from my Android mobile. I am using terminal similar to ubuntu. I am doing copy of my files to laptop and some are being skipped randomly.

When doing ls dir on few directories, files are not listed though I can see those are there and accessible via file manager.
I checked the permission of the directory, all normal. Other files inside another directories are being read by ls and other binaries. All these are present in my home directory.

For example HDoc is a directory inside Download directory inside sdcard/internal-storage. Files are there inside HDoc but not being read by ls or any other binary.
Even tried with sudo.

$ cd sdcard

----- Other working directory permission -----

localhost:/sdcard$ ls -l Download/ | grep -i MAG
drwxrwx--- 2 root 9997    8192 Jun 17 18:49 MAG

localhost:/sdcard$ ls -l Download/MAG/
total 0
-rw-rw---- 1 root 9997   5562037 Feb 16  2021  1.jpg
-rw-rw---- 1 root 9997   2133364 May 29  2023  2.m4a
-rw-rw---- 1 root 9997   1019910 Aug  9  2023  3.png
-rw-rw---- 1 root 9997 671989652 Sep 25  2022  4.mp4


----- Non-readable directory (have files inside)-----

localhost:/sdcard$ ls -l Download/ | grep HDoc
drwxrwx--- 2 root 9997    4096 Jul  8  2023 HDoc

localhost:/sdcard$ ls -l Download/HDoc/
total 0

localhost:/sdcard$ lsattr Download/HDoc/
localhost:/sdcard$

localhost:/sdcard$ sudo su -
root@localhost:~#
root@localhost:~# whoami
root
root@localhost:~#
root@localhost:~# ls /sdcard/Download/HDoc/
root@localhost:~#
root@localhost:~# chmod 600 /sdcard/Download/HDoc/*
chmod: cannot access '/sdcard/Download/HDoc/*': No such file or directory
root@localhost:~#

What could be the reason of not able to read the files inside some directories? Is it 000 permission on those files, but then how come root not able to access? And how come file manager is able to access?

I already tried another terminal too, same issue.