Around a month ago a bunch of my webmention stuff broke on my site, and I just figured out what was causing it. Pushl was getting confused by the fact that I had multiple feeds which provided the same content, and some of them were in a no-webmentions context. The no-webmentions ones were getting processed first, which was preventing the webmention-context versions from actually being processed.
So, I fixed this bug by making the context part of what dedupes the actions.
Every time I work on Pushl I feel like it could use a major rewrite, incidentally. This is one of those times.