Algumas insígnias não são concedidas, embora devessem ser

[Moin]

I have never read about badges requiring the action to be performed on/in the first post.

Is the category the posts are in public?

Badges not granted in non public categories, despite "Allow granting of badges in this category" turned on

It is not currently possible for badges to be granted based on private categories in Discourse. This is an intentional design decision.