The error sounds like you have two servers configured in a "round-robin" cluster configuration and one of these servers isn't getting a complete deployment.
Given the name of the class, "CheckIfClusterIsKdrTask", I'm leaning towards a problem with cluster deployment configuration.
Are you running JBoss/Wildfly in clustered, "HA" mode?
If you're setup for fail-over and/or load-balancing, a quick-fix is to just manually push a full deployment at both servers/nodes. Then, maybe later setup a master controller.
Camunda on clustered JBoss/Wildfly also requires "sticky session" configuration for your load-balancer.
For load-balancing, I've had success using NGINX. Though some still prefer the old HTTP mod_ configuration.