Just provisioned a lab environment based on vSphere 6.7.
Attempting a deployment of an OVA which has a few extra config values in it. Both the H5 and Flash UI error on validation of the OVA with the following message:
The following required extra configurations in the OVF package are not allowed for the deployment: [mem.hotadd]
I can deploy using OVFTool and the --allowExtraConfigs option, and the OVA deploys without error. I could also strip the specific requirement out to see if could get it to work when re-packaged, but that doesn't fix the issue for anyone else if they hit it.
This same OVA deploys without issue to vCenter 6.5 via the Flash Client.