Hello. Thank you for contacting the Toolset support.
I'm not sure why its not working at your end.
Here is a sandbox site and you can auto-login to it using the following link:
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I've created the checkboxes field "venue phase" as you can see here:
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As you can see with the venue post type listing page:
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I've total three posts and out of that "Rockefeller Tower" post is set to phase 1 and posts "CD Tower" and "Platinum Palace" are set to phase 2.
I've created the following view and added the query filter to filter the venue phase custom field with shortcode attribute "phase":
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Select items with field:
Venue Phase is a string equal to VIEW_PARAM(phase)
Then I've added the above view to the following page with view's shortcode as given under:
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