(DOCSP-6502): Add 'known issue' to the Kubernetes Operator (#72)

* (DOCSP-6502): Add 'known issue' to the Kubernetes Operator

* (DOCSP-6502): Add 'known issue' to the Kubernetes Operator

Author: tahiyachowdhury

source/reference/known-issues-k8s-beta.txt

@@ -94,3 +94,14 @@ Machine Memory vs. Container Memory
 
 MongoDB versions older than 3.6.13, 4.0.9, and 4.1.9 report host system RAM, not
 container RAM.
+
+
+Changes to Avoid
+~~~~~~~~~~~~~~~~
+
+The |k8s-op-short| will not be able to apply the following change on a MongoDB Deployment simultaneously:
+
+- The TLS configuration is disabled (``security.tls.enabled: false``)
+- The number of members in a Replica Set is increased
+
+If both operations are applied at the same time, the MongoDB Resource could go into a unrecoverable state.