Note that the trade-off here is a making the subscriptions less robust, i.e. more likely to break completely. Our initial decision here is to make the subscriptions as robust as possible so people can rely on the feature, with the downside of possible conflicts as described here being probably quite rare.

A better solution would be to embed more accurate timestamps (i.e. with seconds) via T230653 to reduce the chance of a conflict. The subscriptions database has been designed to handle the more accurate timestamps.

For reference, the current behavior is documented at https://www.mediawiki.org/wiki/Extension:DiscussionTools/How_it_works#Tracking_topics.

At least, all related talk pages should be displayed on Special:TopicSubscriptions.

T306373: Update Special:TopicSubscriptions to use permalinks would allow this.

Relaying a bug report from a Convenient Discussions user. It illustrates how these conflicts may occur in the field (another common case is MassMessage btw):

Dear colleague. The Russian Wikipedia has a bot called Dibot, which automatically transfers new articles from the Incubator to the “Requests for deletion” page; it often transfers several articles in a batch. And so, if you try to subscribe to discussions of one of the sections of such a batch - either by clicking the "Subscribe" button or by writing a remark in the section - CD subscribes to all sections of the bot-batch, but only to the entire batch; it is impossible to subscribe to one section. Notifications are sent separately for each section. When I try to unsubscribe, it unsubscribes from all sections of the pack. Example page: https://ru.wikipedia.org/wiki/Project:К_удалению/27_февраля_2024, sections No. 6 to No. 9. -- Tomasina

Note that the section titles here are different, only the timestamps and usernames are the same.