During Startup you may see that error message on your standby database. I faced with that error message on 12.2 on linux os.
The above error is caused because of the following parameter set to NONE in standby whereas it has been set to TYPICAL in primary database.
So we have altered the below parameter to TYPICAL in standby and the above warning cleared.
So If you set this parameter to NONE or TYPICAL on both site you will not see that error message anymore.
Enabling lost write detection is crucial in a Data Guard setup. Lost writes are detected at read time which allows to perform recovery steps much earlier than without it. Nevertheless, lost writes should not occur. If it does occur, something really bad is going on in your environment and you need to investigate the root cause of the lost write.