adfs/ls does not work while adfs/ls/idpinitiatedsignon works | There are no registered protocol handlers on path /adfs/ls/ to process the incoming request

Hello Experts

I am trying to configure ADFS 3.0 with Sharepoint 2013 and facing an issue with ADFS 3.0 url

When I try to access url https://<ADFS.domain.com>/adfs/ls - I face following error 

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Encountered error during federation passive request. 

Additional Data 

Protocol Name: 

Relying Party: 

Exception details: 
Microsoft.IdentityServer.RequestFailedException: MSIS7065: There are no registered protocol handlers on path /adfs/ls/ to process the incoming request.
   at Microsoft.IdentityServer.Web.PassiveProtocolListener.OnGetContext(WrappedHttpListenerContext context)

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But When I try to access ADFS url - https://<ADFS.domain.com>/adfs/ls/idpinitiatedsignon 

It works.. 

Is it normal behavior or something wrong here.

Please suggest.

Thanks