Why new Guard relays experience temporary drops in traffic

When a relay first becomes a Guard, it may see a temporary drop in traffic as clients gradually rotate in new Guards. This is normal behavior in Tor's design.

Since it's now a guard, clients are using it less in other positions, but not many clients have rotated their existing guards out to use it as a guard yet. Read more details in this blog post or in Changing of the Guards: A Framework for Understanding and Improving Entry Guard Selection in Tor.