We have a matrix job with "SSH Agent" enabled in "Build Environment" with credentials and a post-build action of "Execute Scripts On Matrix" with a shell command that requires those credentials.

We recently upgraded from Jenkins v2.249.3 to v2.263.1 (and potentially upgraded some plugins at the same time, though I don't believe that we upgraded any of the ssh-related ones.) The aforementioned shell command now fails because it no longer has access to the ssh credentials it requires.

Comparing the parent logs, we see a new call to "ssh-agent -k" in the Jenkins v2.263.1 parent job log immediately after the matrix children complete and before "[PostBuildScript] - [INFO] Executing post build scripts." that wasn't present with Jenkins v2.249.3.

It would appear that the agent is being killed by Jenkins v2.263.1 whereas it wasn't with Jenkins v2.249.3. I was unable to find a setting that controls this.

(We also upgraded from Debian 10.6 to Debian 10.7 at the same time, which meant upgrading from openjdk-11-jre-headless from 11.0.9+11-1~deb10u1 to 11.0.9.1+1-1~deb10u2 which seems unlikely to be the cause.)