My guess is at some point they changed this and now any new ones use the airtable:mention approach, but any old notes in their database created before a certain date have the old markdown format so when querying for those it still comes in with that format.
If anyone else had issues with this I’d be curious to hear.
@openside I’d recommend taking this one directly to Airtable’s support team. They should be able to investigate further. I am only seeing the <airtable:mention> format and have never seen the other format before.