The reason for it is most likely that your system uses tmpfs for /tmp and runs out of space during the patching process.

In my case, I encountered this issue when using the free Veeam Agent for Linux on a system that is running TUXEDO OS, which is based on Ubuntu 22.04 LTS.

To fix the issue, I created a separate directory on my root drive and assigned it within the [core] section of the veeam.ini config file as tempFolder.

To do so follow this steps:

1. Create the separate directory (you can basically create it wherever you want, just make sure you have enough free disk space at its location):
   sudo mkdir /.veeam-tmp

2. Open the Veeam config file /etc/veeam/veeam.ini and add the line tempFolder = /.veeam-tmp within the [core] section:

    ...
    [core]
    ...
    # Custom temp folder
    tempFoler = /.veeam-tmp
   

Note: to patch the Recovery Media you also need to install the package squashfs-tools manually, otherwise you will receive an error as well. To do so execute:

sudo apt install sqashfs-tools