In createUiDefinition.json the Microsoft.Common.ServicePrincipalSelector type only accepts true or false for the visible property, not a variable boolean like other types

If I put in a variable boolean in the visible field it does not resolve the expression properly, it seems to just revert to the default true. Here is an easily verifiable example:

{
  "$schema": "https://schema.management.azure.com/schemas/0.1.2-preview/CreateUIDefinition.MultiVm.json#",
  "handler": "Microsoft.Azure.CreateUIDef",
  "version": "0.1.2-preview",
  "parameters": {
    "config": {},
    "basics": [],
    "steps": [
		{
			"name": "visibilityTest",
			"label": "visibilityTest",
			"elements": [
				
            {
                "name": "enableVis",
                "type": "Microsoft.Common.CheckBox",
                "label": "Toggle SP Selector Visibility",
                "constraints": {
                    "required": false
                }
            },
            {
                "name": "SPSelector",
                "type": "Microsoft.Common.ServicePrincipalSelector",
                "label": {
                    "password": "Leave Blank",
                    "certificateThumbprint": "Certificate thumbprint",
                    "authenticationType": "Choose Password",
                    "sectionHeader": "Leave this section as default"
                },
                "defaultValue": {},
                "options": {
                    "hideCertificate": true
                },                
                "visible": "[equals(steps('visibilityTest').enableVis, true)]"
            }

			]
		}
    ],    
    "outputs": {}
  }
}

The only thing that will hide the ServicePrincipalSelector is the value false. Every other attempt to hide it based on an expression causes it to be visible. Please advise if I am doing something wrong or if a fix can be made.