NFT Resyncing - New fields

I know you guys made some big changes to your metadata resync update with more granular sync dates (new fields last_token_uri_sync or last_metadata_sync)

I noticed some of the NFTs have null values for one of these fields or both.

That said, I’d like to know in which scenarios it could happen?
When should resync endpoint be called for these situations?

Hmmm do those NFT have metadata? Now Moralis should be syncing metadata automatically, you can check this post here

those fields were recently added, not all the nfts have them now as not all the nfts got metadata resynced since those 2 fields were added