Zookeeper fails to upgrade after upgrading operator

[kobo-gcyre]

After upgrading the solr operator to 0.7.1 the zookeeper operator doesn't upgrade the zookeeper pods. found these errors in the logs

{"level":"error","ts":1694631591.8541024,"msg":"Reconciler error","controller":"zookeepercluster","controllerGroup":"zookeeper.pravega.io","controllerKind":"ZookeeperCluster","zookeeperCluster":{"name":"solr-stage-solrcloud-zookeeper","namespace":"solr-stage"},"namespace":"solr-stage","name":"solr-stage-solrcloud-zookeeper","reconcileID":"80330bbc-7a87-41db-9e5b-0d06a74c40fc","error":"Operation cannot be fulfilled on zookeeperclusters.zookeeper.pravega.io \"solr-stage-solrcloud-zookeeper\": the object has been modified; please apply your changes to the latest version and try again","stacktrace":"sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).processNextWorkItem\n\t/go/pkg/mod/sigs.k8s.io/[email protected]/pkg/internal/controller/controller.go:273\nsigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).Start.func2.2\n\t/go/pkg/mod/sigs.k8s.io/[email protected]/pkg/internal/controller/controller.go:234"}

zookeeper operator pod is using 0.2.15

 Image:         pravega/zookeeper-operator:0.2.15

but statefulset is using an older version

image: pravega/zookeeper:0.2.13

after the operator upgrade why are those errors showing up?
why doesn't the zookeeper operator update the version in the statefulset?