This is not a known problem. Can you give us an example what you mean?

I have seen automatic appending from services like Wandrer, Bandok, and some other weather and training apps, but not from a supplement. Have a look at some of your settings such as https://www.strava.com/settings/apps and https://www.strava.com/settings/partner_integrations if they are all services you recognize.  

Perfect. Thank you. It was under apps in settings.