Linked models are usually inserted using Origin to Origin, or by Shared Coordinates.
To check this, select the link, then check Properties.
There should be a setting there under "Other", called Shared Site. If so, click the button and see what it says.
It may ask you to Move Instance, Record current position ( don't pick that! since you accidently moved the link)
or Do not share site of selected instance.
You will likely need to use Move Instance, and select the Shared Location from the box at the right.
Click on Understanding Shared Positioning for Help on this topic.
Cliff B. Collins
Registered Architect The Lamar Johnson Collaborative Architects-St. Louis, MO