Datalayer variable not picking up boolean value

I’ve got a _mtm Data Layer object that looks like this

event: "mtm.Pageview"
isLoggedIn: false
market: "US"
pagePath: ""
pageTitle: "Search"
pageType: "Search"

I want to pick up the properties isLoggedIn, market and pageType as custom dimension using Data Layer variables.
Market and pageType works fine, but the isLoggedIn isn’t picked up by the Datalayer variable, even though it’s showing up in the Data Layer tab in the debugger.

Doesn’t the Data Layer Variable support boolean values?