Well, just so you know, I've just run into the same bug haha. I'm using BWS' successor, EE Mod tool despite the controversies around it.

I'm almost certain this odd out of place text in the Radiant heart is caused by the component that slightly improves Wizard Slayers. Cant fathom why it would place this text there, but so far its been my only issue and its not overly gamebreaking I suppose. Definitely odd. Zooming in hides the text and it doesn't break anything but there's an issue somewhere, obviously.