It probably just doesn't fit into your text object.
Try using a text input (disabled) instead.
Also try to avoid updating text every tick in general. Update when it changes instead.
It's not to do with the text object space as I checked it, there is a genuine problem as though it doesn't like the format or something. But at the same time I'm not sure why you would ever need to display the json on the FE, I don't see a need for it. That's why I'm asking as storing it in a variable should be enough.