Thanks a lot for your help. I have found the issue. When I created those instances for HDP, I forgot to remove ephemeral storage from the instance. So what happened then that during installation the Oozie data directory was pointed to /mnt/hadoop/oozie/data by default. I thought unless I mention during installation, it will not use /mnt point for oozie or other services.
As a result, after I stop/start the instance all data in that mount point (ephemeral storage) got lost and hence Oozie didn’t find the schema. This is also the reason behind the issue with the namenode formatting (my other thread related to HDFS).
To be sure about that, I just installed HDP 1.3.2 again in another cluster and this time I removed ephemeral storage from the instances. So, this time Oozie data path is pointed to /hadoop/oozie/data. Now everything seems working and even “Start All” and “Stop All” buttons are working as expected. Namenode issue also resolved now.