The project recently switched from all JIRA events being sent to the dev mailling list, to just issue creations. This seems like a good thing because the dev mailling list was very noisy before, and if you want to see all the JIRA comments etc you can subscribe to the JIRA list. If you don't subscribe to the JIRA list you need to take the time to become a watcher on each issue that interests you.
However, the flip-side of this is that when you comment on a JIRA you have no idea who's going to get notified (apart from the watchers). In particular, commenters don't know whether any of the committers will see their comment, unless they mention them individually by name. But for an issue in which no committer has thus far taken an interest, who is the commenter to @mention? There is no @kafka_commiters that you can use to bring the comment to the attention of the whole group of committers. There is also the fact that there are an awful lot of historical issues which interested people won't be watching because they assumed at the time that they'd get notified via the dev list. I can well imagine that people who aren't working a lot of Kafka won't realise that there's a good chance that their comments on JIRAs won't reach relevant people. I'm mentioning this mainly to highlight to people that this is what's happening, because it wasn't obvious to me that commenting on a JIRA might not reach (all of) the committers/interested parties. Cheers, Tom