That was my first guess… and a good one.
In this case, though, those items are moved, not deleted. They moved from Level 21 to Level 23 on April 18th. And note that @chezmax is on Level 22.
I assumed that if they were unlocked already, the reviews would continue as normal, but that doesn’t appear to be the case.
Today, I’m putting together a tiny page on wkstats.com for people to submit their APIv2 keys to me for troubleshooting, so I don’t have to post my email address every time I need an API key. I’ll post the URL when it’s done.
Anyway, I suspect this may indeed be an issue for viet and oldbonsai. I won’t know for sure until I’ve seen if there’s anything in the API data that I can use to distinguish items like this.