[BUG] Manual notification does not seem to work

[Dreamsorcerer]

Describe the bug
I'm not clear what is happening after enabling manual notifications, the notifications seem to either arrive before the workflow triggers that should send the notification, or it appears significantly after.

To Reproduce
This PR for example: aio-libs/aiohttp#12240
The workflow succeeded 13 hours ago: https://github.com/aio-libs/aiohttp/actions/runs/23098834822/job/67096304511
But the notification has only appeared a few seconds after clicking merge (which is a bit late to be useful): aio-libs/aiohttp#12240 (comment)

Expected behavior
Notification should appear when the workflow runs, not before and not hours after.

[linear]

CCMRG-2131

[Dreamsorcerer]

By contrast, this PR, the notification appeared 8 minutes ago, but the CI job to trigger the notification hasn't run yet.
aio-libs/aiohttp#12354

[Dreamsorcerer]

As far as I can tell, setting notifications to manual does absolutely nothing and it continue to follow default behaviour.