The recall is being issued because the harness locking and release button does not always return to its locked position, which can allow the harness adjustment strap to slip back through the adjuster as a child moves around in the seat. This can result in a loose harness, increasing the risk of the child being injured in a crash.
The affected seats were manufactured between May 1, 2008 and April 30, 2009. A list of the affected models can be found through the link below.