Each of the release notes for 1.2.13, 1.3.6, and 1.4.0 have:
* client: recover from panics caused by artifact download to prevent the Nomad client from crashing [[GH-14696](https://github.com/hashicorp/nomad/issues/14696)]
Please bump to 1.2.13.
HashiCorp Nomad and Nomad Enterprise 1.0.2 up to 1.2.12, and 1.3.5 jobs submitted with an artifact stanza using invalid S3 or GCS URLs can be used to crash client agents. Fixed in 1.2.13, 1.3.6, and 1.4.0.
This is fixed in the tree.