Using a FormatText node with Specifier in the same graph as an empty Macro will freeze the editor

Using a FormatText node with Specifier in the same graph as an empty Macro will freeze the editor. Not using the Specifier or deleting the unused Marco will allow the BP to compile fine.

**Only reproducible in the users project

User Description:

This is a freeze-on-compile issue I've been having migrating my working 4.10.4 project to any future version through the current 4.12.2. I have narrowed it down to the "format text" blueprint node. Attached is a video demonstrating the issue, and a very stripped-down version of my project that demonstrates the issue.

Some PC specs: Windows 8.1, i7-4930K, GTX Titan original, 32GB RAM. Malwarebytes anti-malware, though turning it off doesn't fix the issue.

I have drastically reduced the project into the simplest possible thing that still triggers the freeze, downloadable here: [Link Removed]

Here's a diagram of all the blueprint: [Link Removed]

There's an unused macro in the "MacroLibrary.uasset" called "This macro casts to pawn and nothing else". Its presence in the macro library, even though it's not used in any blueprint graph, is part of what causes it to freeze. There's another macro in the library called "A totally empty macro"; placing that one into the pawn's event graph is also necessary. And finally, the format text node with an extra input is the seemingly essential 3rd ingredient.

**Only reproducible in the users project

1. Open the attached test project
2. In the Content Browser > Blueprints > open "AViD_Player_MkII"
3. Open the Event Graph to see the setup
4. Attempt to compile the BP

Results: The editor will freeze

Expected: For the BP to compile without issue