ACL problem

Good morning sirs,
I use dar and I find it very usefull. There is some time that when I 
lunch a full dar backup I get the following error:

$ /usr/local/bin/dar -Q -R "/media/src_backup" -c 
"/media/serverdati_hd3/2019-08-23/home_201908232236_full_Fri" -P 
no-backup -P shares/.archivio -D -z -an -Z *.7z -Z *.jpeg -Z *.jpg -Z 
*.nww -Z M019_M286_Ceneri-201703131214.ods -Z *.odt -Z 
M280_PCS_PCI_Calorimetro-201607061000_html_6a9bcf4b.png -Z *.zip -ac  -s 
700M -E "/usr/local/sbin/bkdar_make_room.sh serverdati_hd 700"

Error while saving 
/media/src_backup/shares/DAE/Produzione/Merceologici/2017/GESENU/1712906_Ponte 
Rio_24-25ago17/1712906-008_FOU.docx: Error while reading from file: 
Input/output error
Error reading EA for 
/media/src_backup/shares/DAE/Produzione/Merceologici/2017/GESENU/1712906_Ponte 
Rio_24-25ago17/100CASIO : Error retrieving EA list for 
/media/src_backup/shares/DAE/Produzione/Merceologici/2017/GESENU/1712906_Ponte 
Rio_24-25ago17/100CASIO : Input/output error
[...]
Error reading directory contents: Cannot read inode for 
/media/src_backup/shares/DAE/Thumbs.db : Input/output error . Ignoring 
file or directory
Error reading directory contents: Cannot read inode for 
/media/src_backup/shares/DAE/MEZZI : Input/output error . Ignoring file 
or directory
Error reading directory contents: Cannot read inode for 
/media/src_backup/shares_tutti.acl : Input/output error . Ignoring file 
or directory
Error while saving /media/src_backup/shares_fdp.acl: Error while reading 
from file: Input/output error
Error while saving /media/src_backup/gruppi: Error while reading from 
file: Input/output error

If then I execute an incremental dar backup dar doesn't find any 
problems and add the files that have skipped during the full backup, acl 
included.

The dar I use is a little bit old:
$ dar -V

  dar version 2.4.22_interim1, Copyright (C) 2002-2052 Denis Corbin
    Long options support       : YES

  Using libdar 5.6.7 built with compilation time options:
    Libz compression (gzip)    : YES
    Libbz2 compression (bzip2) : YES
    Liblzo2 compression (lzo)  : YES
    Strong encryption          : YES
    Extended Attributes support: YES
    Large files support (> 2GB): YES
    ext2fs NODUMP flag support : YES
    Special allocation scheme  : YES
    Integer size used          : 64 bits
    Thread safe support        : YES
    Furtive read mode support  : YES
    Detected system/CPU endian : little
    Large dir. speed optimi.   : YES

  compiled the May 16 2016 with GNUC version 4.7.2
  dar is part of the Disk ARchive suite (Release 2.4.22_interim1)
  dar comes with ABSOLUTELY NO WARRANTY; for details
  type `dar -W'. This is free software, and you are welcome
  to redistribute it under certain conditions; type `dar -L | more'
  for details.

Someone knows why dar return this error during the full backup?

Piviul