Difference Between CVE Online Database and Weaknesses in Defender Security Center

Can anyone give me an idea as to why there might be a discrepancy between the results I find for a particular product when searching the CVE online website and what I find when searching for the same product in the Defender Security Center?  I find 25 results online but only 22 when searching through the Defender Security Center.  Is there perhaps a lag time between when an item is listed in CVE versus when it is added to the Defender Security Center?  Any insight or direction is appreciated.  Thanks!