ULS auto-adds languages to "Suggested languages" and to Compact Language Links if they were clicked, and according to browser, geolocation, etc.
This is not supposed to be a problem; what's important is to show the useful languages, and the less useful ones will fade out as time passes. However, some editors said that this is inconvenient, and that it would be nice to have a way to remove languages that they don't need actively.
While not a high priority, it would be nice to make it possible some day.
Closely related, but distinct issue: T96547. Perhaps the design for both can be done together.