ERROR scan: Readdirnames XXXXXXX failed: readdirent: input/output error XXXXXXX

Hello, I am making a security copy from a pendrive encrypted in Windows and mounted in Linux with DISLOCKER. It is a pendrive with many files.

When I made the last backup copy and it happened to me in previous ones, it showed me these two errors (on other occasions it was with other files but also with two or very few):

restic -r ~/restic/copia_pen/ --verbose backup /media/bitlockermount

open repository
enter password for repository:
repository 7da4114a opened successfully, password is correct
lock repository
load index files
using parent snapshot 3275745d
start scan on [/media/bitlockermount]
start backup on [/media/bitlockermount]

scan: Readdirnames /media/bitlockermount/XXXXXXXX failed: readdirent: input/output error XXXXXXXXXX (I have replaced the path with XXXX for confidentiality)

scan: Readdirnames /media/bitlockermount/XXXXXXXX failed: readdirent: input/output error XXXXXXXXXX

scan finished in 136.579s: 28876 files, 62.369 GiB

[6:58] 68.02% 19731 files 42.424 GiB, total 28876 files 62.369 GiB, 0 errors ETA 3:17 /media/bitlockermount/XXXXXXX uploaded intermediate index 2632d352

Files: 125 new, 28756 changed, 0 unmodified
Dirs: 0 new, 1 changed, 0 unmodified
Data Blobs: 119 new
Tree Blobs: 2 new
Added to the repo: 88,361 MiB

processed 28881 files, 62.369 GiB at 9:41
snapshot d7f17c65 saved

If I check the backup it doesn't show any errors.

restic -r ~/restic/copia_pen/ check

using temporary cache in /tmp/restic-check-cache-953700429
enter password for repository:
repository 7da4114a opened successfully, password is correct
created new cache in /tmp/restic-check-cache-953700429
create exclusive lock for repository
load indexes
check all packs
check snapshots, trees and blobs
no errors were found

If I try to mount the backup, it mounts without errors.

If I compare the latest Snapshot with the original pendrive using FreeFileSync, it shows no differences.

Aren’t they actually fatal errors? That is, have you been able to correct them and do they not affect them? They are quite long routes, I don’t know if it can affect

EDIT: Using FreeFileSync in content comparison mode it does detect 3 different files, in two I don’t see differences but in one I do see a small difference in the image printed in a .doc document. None of those files are the ones that marked errors in the copy.

Solved, it was a problem with my pendrive, I have formatted it and this no longer happens.