Please tag posts as NSFW even if they're already in a NSFW community. It's not redundant.
I'll pin this for a day.
Due to there being potentially different implementations of the ActivityPub protocol such as Lemmy, Mastodon or Kbin it's not always guaranteed that an image in a NSFW community will be hidden or flagged by default.
Please make sure you flag your individual posts as NSFW as well.
We're in the very early stages of Lemmy/kbin and there's still many things to iron out. It sucks but things will go better and easier over time.
If you have some time please check your post history to make sure your images are tagged correctly.
Guess other instances do not care regardless even if its correctly flagged and tagged and everything. I had a discussion about this topic with the mods of feddit.de, but they are firm to block whole instances if there is any NSFW community on it. No matter what. I am now on kbin and deleted my account there.