When a user who has "subscribe by default" enabled creates a new, level-3 entry (under a "===" subheading) on pages like:

https://meta.wikimedia.org/w/index.php?title=Steward_requests/Global&oldid=29218175

they are subscribed to the whole level-2 ("==") subsection (aka "topic"); in this case "Requests for global (un)lock and (un)hiding".

They then receive notifications for every new update to any entry in that subsection, of which at the time of writing the example page has over 100.

Instead they should be subscribed (or able to choose to be subscribed) only to the level-3 subsection which they created; such as (on the example page) "Global lock for TimiEnglish".

It may perhaps be useful to make it possible to set "use level 3 for subscriptions by default" using a magic word on the page.