what is flooding /var/tmp?

["sp007@caiway.net" <sp007@caiway.net>]

Hello,

My /var/tmp directory gets flooded by big files named:

sort01ei1t
sort01Eq7u
sort01sLAs
...
sortzZZtvv


the files are approx. 13 Gb each.
In 24 hours > 6000 are written.

My big partition is filled by it until the system freezes.

The files are plain text files, containing sshfs paths:

/mnt/nas/sshfs/proc/self/task/413551/root/proc/self/task/413551/root/proc/self/task/413551/root/proc/self/task/413551/root/proc/
.........

nas and desktop are running debian 11 daily updated.

How can I find out which program is writing these files?

Thanks!