In early 2020, I lost a wmtc post that was important to me and had a lot of comments.
Allan and I were able to re-post the post itself, but in the process, a huge chunk of the blog disappeared. Coincidentally, I had recently done a back-up using Blogger's export/import function -- the first time in years, which is awful and scary.
However, the most recently exported file wouldn't upload. Blogger's import/export function was always problematic, and Allan and I (and several other bloggers) used the Blogger Help Community to bring this to Blogger's attention.
Eventually Blogger fixed the export/import issues. But I was still never able to upload that one backup file.
The upshot of all this: thousands of comments on this blog between July 2006 and May 2019 were lost. I was gutted.
A few weeks ago, for some reason I checked spam comments, something I hadn't done in a very long time. I was astonished to find 95 comments there -- all from 2006, by people who were regular readers and commenters at the time! Lost comments had returned!!!
I was able to put the comments through, and they appear normally on those old posts.
Since then, I check spam comments daily or almost daily. The folder always contains old comments by known wmtc commenters, and I put them through. There have been about 250 so far.
This is a very welcome development!!
It's possible that Allan and I inadvertently hurt this process -- one we never could have anticipated -- as we were repairing damage to wmtc. Many URLs have changed. (That's why I updated many internal links.) Now I wonder if lost comments will appear for posts with changed URLs. If comments on those posts do come in, will they post when I moderate them?
Meanwhile the old comments continue to appear, and I continue to put them through. I have zero information on why this is happening.