When deploying a Spring Boot application I hit a problem that my application was being OOMKilled due to the default settings provided by Knative Serving operator being too low. 

When I updated the default values (see below) for memory, the application was successfully deployed. However after I removed those values from the default section or set the value to an empty string (revision-memory-request: '') the previous value was still stored on config-defaults.  Seems like the operator is not updating the config map properly.

To reproduce:

Deploy a knative service without specifying mem values. 

Update Serving defaults for memory by setting it to empty or remove it from the default section. 

Deploy the service and check the value for memory and verify config map values.

Default section of Serving CR 

defaults:
  revision-cpu-limit: 1000m
  revision-cpu-request: 400m
  revision-memory-limit: 444m
  revision-memory-request: 333m
  revision-timeout-seconds: '300'
deployment:

Check configmap 

oc get configmap config-defaults -n knative-serving -o yaml