UTM tracking problems — what causes the most issues?

Hi everyone! 👋

I built Free UTM Builder & Checker to make campaign tracking easier.

It lets you create UTM URLs, check existing campaign links for common formatting issues, and see the expected GA4 channel before using a URL.

I'm curious: what UTM or campaign-tracking problem causes you the most trouble?

I'd love to hear how other marketers, bloggers, and small businesses handle UTM tracking.