Shadow bans are the province of admins not sub moderators. However there are sitewide automod rules that will flag some sites as spam (or some users) which will automatically pop up in the mod queue and will need to be manually approved by the mods. However when an item is reported like this it is not clear why it is marked and so maybe just removed from the queue out of a need to keep it clear.

The best course of action is to contact the mods of the sub and ask them why a submission has been removed. Assuming your account does not look like a spammer or a newbie account then they will look at it and can decide retroactively to approve it or suggest you resubmit it again and they can make sure it gets approved manually then.

Hope that clears up some confusion.