When excerpting news articles, I sometimes encounter invisible Word Joiner characters, randomly inserted. Symptomatic of LLM-generated text. Even seen blog posts with broken links because such chars were lurking in urls. I found a site that identifies & cleans em from pasted text.
Unicode Character Analyzer
https://kovart.github.io/invisible-text/
This site offers a similar service & says OpenAI called em a quirk not watermark.
https://invisiblecharacterviewer.com/characters/word-joiner
Reuters, BBC, Guardian AI policies
https://www.niemanlab.org/2026/07/how-three-newsrooms-are-charting-different-paths-for-ai-use/