I can confirm that the issue you are experiencing is still present in vSphere 6.5 as per Re: Unable to deploy OVF/OVA Template - vCenter 6.5d (Build 5318154) the easiest work around is to deploy the OVA/OVF using a direct connection to the host (https://<HostIPorHostName>/ui), or use the OVF Tool CLI
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Cheers,
