First and subsequent citations

Hi! I’m using EndNote X8. All my references are imported from PubMed as citation files (.nbib). One (only one!) of my citations in APA 6th style shows up in a subsequent format (Author et al, Year), instead of as a first format (First THREE authors et al, Year). All other citations show up properly in the document. I have re-imported the reference, updated within the document, and tried updating the APA style to no avail. I am using the DEFAULT APA 6th style and therefore have not attached, here. Thank you in advance for your help! 

If there is only one citation that is not matching your expectations, it is likely to be caused by some other settings?  – What happens if you put that citation in a short document with no other citations?  Does it still display the wrong thing, or does it only do it when other records are cited?