For about a week, many sites saw their ChatGPT referral traffic fall while direct traffic rose. The cause was not a real change in visitor behavior. ChatGPT links appeared to stop carrying the utm_source=chatgpt.com parameter that OpenAI introduced in June, and OpenAI has since confirmed it was a bug and begun rolling out a fix, Search Engine Land reported on October 20.
What Went Wrong
Adobe's Cedric Huesler flagged that ChatGPT links were also opening in a way that suppressed referral information. With both the UTM parameter and the referral data missing, analytics platforms had no way to credit ChatGPT and may have filed the visits under direct traffic instead. The issue followed the GPT-6 release.
Timeline of the Fix
Huesler contacted OpenAI on October 14, and the company confirmed a known bug with a fix expected that week. The fix began rolling out early on October 15. By 9 a.m. Pacific Time that day, tagged ChatGPT clicks had recovered to roughly 95 to 100 percent of the levels seen in the same hour the previous week, based on telemetry covering thousands of domains.
What the Data Showed
Huesler looked at about 500 pages where ChatGPT previously made up at least 5 percent of visits, comparing October 9 to 13 with the week before. ChatGPT traffic dropped by about 31,000 visits a day, while direct traffic on the same pages rose by about 26,000 a day. Search traffic fell 7 percent, in line with broader search trends. Two-thirds of the pages that lost ChatGPT referrals saw direct traffic climb, and the newly classified direct visits behaved much like the ChatGPT visits identified earlier.
What Marketers Should Do
The apparent loss came from misclassification, not a real decline in visits. A few steps follow from that:
- Annotate October 8 to 15 in GA4 or Adobe Analytics so the temporary ChatGPT dip and the matching direct-traffic rise are explained.
- Avoid changing attribution models in response to the dip.
- Keep using UTM tracking. Referral information is still missing from most ChatGPT clicks, so utm_source=chatgpt.com remains an important attribution signal.
- Review referral trends, direct traffic and landing-page performance together before judging how well ChatGPT is working for you.