Recalled seats use a harness crotch buckle which may become resistant to unlatching over time, due to exposure to various contaminants (like food and drinks) that are present in everyday use of the convertible car seat or harnessed booster by toddlers. This condition may make it difficult to remove a child from the vehicle. There is no such risk if the buckle is functioning normally.
The link below to the Evenflo web site lists all affected models and instructions on what to do if you own a recalled seat. The link below in Spanish translates the text of the web site, but does not include the additional links.