Isn't your wife a U.S. citizen? According to this, records are not available for a U.S. citizen:
https://i94.cbp.dhs.gov/I94/#/history-search
For Your Info
United States Citizens and Lawful Permanent residents are unable to look up their prior 10-year travel history at this time.
The provided travel history may not reflect the following: land border arrivals/departures, closed loop cruise arrivals/departures, air carrier reservation updates, and/or United States Citizenship and Immigration Services (USCIS) updates, changes of status, extensions of stay or adjustments of status.
U.S. Citizen and Lawful Permanent Resident
travel is NOT provided on this website. If this travel history is not complete, there is no action to take. CBP documents come from a variety of sources. This travel history is only a tool to assist the public and is not an official record for legal purposes.
Did she have to file a FOIA request for her
land PoE exit/entry data, beyond the I-94 request?