ADF V2 failure when using bool variable

Very simple issue. I am trying to set up a pipeline that has a variable of type bool. As soon as I add it, the pipeline fails with:

{
"code":"BadRequest",
"message":"Invalid value for property 'type'",
"target":"pipeline/pipeline2/runid/66b9c7be-9894-494a-abd9-34fd92bbd972",
"details":null,
"error":null
}

simple pipeline with a string variable and a wait activity succeeds.

{
"name": "pipeline2",
"properties": {
    "activities": [
        {
            "name": "Wait1",
            "type": "Wait",
            "typeProperties": {
                "waitTimeInSeconds": 1
            }
        }
    ],
    "variables": {
        "Test": {
            "type": "String",
            "defaultValue": "\"Hello\""
        }
    }
}
}

When I add a bool and nothing else, it fails to debug.

{
"name": "pipeline2",
"properties": {
    "activities": [
        {
            "name": "Wait1",
            "type": "Wait",
            "typeProperties": {
                "waitTimeInSeconds": 1
            }
        }
    ],
    "variables": {
        "Test": {
            "type": "String",
            "defaultValue": "\"Hello\""
        },
        "TestBool": {
            "type": "Bool",
            "defaultValue": false
        }
    }
  }
}

Any clue how to get this to work? I am trying to use this variable as a condition for an Until loop.
Many thanks.

ok, I experimented.

If I go into the code and set the type as boolean rather than Bool, then the above pipeline runs.

Looks like a UI bug in the designer that sets the type to Bool. I'll file a bug report. Mark.

Update ok it runs but I can't set a default value (it disappears) and anything that references the value causes an Internal Server Error (presumably because it is null which is invalid for a Boolean). Definitely something for the engineers to look at.

Update 2 It appears you can set the variable with SetVariable without error but it appears not to do anything. The value is always true in my test case.

Update 3 Microsoft has a fix coming next week.