There is no way your grocery store has lettuce from two different vendors and isn’t labeling the difference.

You could wonder if the distributor is commingling. Milk production, probably. They’re taking responsibility for the quality of the final product, though.

The arugula issue a few years back revealed that whilst they’re technically labeled it wasn’t in any customer-identifiable way (serial number shenanigans).

Now the location is clearly printed on each bag.