Even though the Format Text node does not have any execution pins it is possible to put a breakpoint on the node.
NOTE: The breakpoint appears as a yellow circle and does not trigger when the code is ran.
1. Open UE4 Editor (any project)
2. Open Level Blueprint
3. Right click and add a Format Text node
4. With the node selected press F9 to add breakpoint
Head over to the existing AnswerHub thread and let us know what's up.