Mixpanel CSV Import Issue: Missing Poly_alloted_2 Values Explained

Hi all, I uploaded a CSV to Mixpanel with two columns: distinct_id and Poly_alloted_2. Out of ~14,000 users, only around 6,000 profiles show the Poly_alloted_2 value. The remaining ~8,000 show it as undefined ,even though the CSV has valid values for all rows, and all distinct_ids exist in the user profiles. Both fields were mapped correctly during import. Would really appreciate any help if someone has faced this or knows what might be going wrong.