We are releasing Nomad 1.2.2 which contains a bug fix for a server panic in the scheduler affecting clusters that contain clients with a mix of node classes and run system or sysbatch jobs that target a subset of them. This bug only impacts Nomad (and Nomad Enterprise) 1.2.0 and 1.2.1.
Users should upgrade to Nomad 1.2.2 to avoid this problem.
The Nomad Team
1.2.2 Changelog - nomad/CHANGELOG.md at v1.2.2 · hashicorp/nomad · GitHub
1.2.2 Binaries - Nomad v1.2.2 Binaries | HashiCorp Releases