My root partition was full as hinted by seablade and Paul. I had to schedule a clean up of the /tmp and /var/tmp/ that wasn’t set by the Tumbleweed by default. Something related to systemd as I read in the opensuse forums.
That was all.
Thanks a lot for the answers.
For future reference, there’s a --target option to unzip the temporary bundle to some place other than /tmp if disk-space is scarce there. (see also sh Ardour*.run --help)