Yes that is true.
I used a coding agent to summarise when emails are suppressed in mailing list mode:
- The user muted the topic, category, or one of its tags.
- The user muted or ignored the author.
- The user cannot access the post - for example, it is in a restricted category.
- The account is inactive, silenced, suspended, or awaiting required approval.
- The user chose to exclude their own posts.
- The post or topic was deleted before delivery.
- Previous delivery failures pushed the user’s bounce score over the configured threshold.
but you can look at the code yourself: