@simonwoods Okay. So I think I’ve sorted this out: in that long post that kept reposting, I had a link to several micro.blog posts (including one of yours). That one post was showing up as like three replies in the timeline.
For my own reference (and others that I may point here), I did this to solve it:
I don’t send Webmentions to any micro.blog links that are in the main text of my posts. I don’t include micro.blog replies in my blog’s feed. They will only show up as duplicates, since they are already sent as Webmentions. There is no need to attach an @-style username to the main text, since these are automatically added by the Webmention.