Unmasking the procMount will allow more information than is necessary to the program running in the containers spawned by Kubernetes.
The default /proc masks are set up to reduce attack surface, and should be required. Make sure your Kubernetes workload configuration has the securityContext field 'procMount' parameter is set to default. For more information, see the Kubernetes documentation.
References:
https://kubernetes.io/docs/concepts/security/pod-security-standards/