Can I be positive for a particular food on Vibrant Lectin Zoomer but negative for this Food on Vibrant Food Sensitivity or vice versa?

Yes. Vibrant's Food Sensitivity test measures antibodies to whole food protein extracts. Vibrant's Lectin Zoomer test measures antibodies specific to the lectin peptides within foods. Antigen-to-antibody binding is very specific. Therefore, someone may produce antibodies to an entire food protein or only a single part of it (a peptide fragment in it).