For a course, the Announcements navigation link says "No content, not visible to students" - even though there is a first announcement posted. And indeed it not visible in student view.
I checked all other possible issues I could think of: The course is published, "Announcements" is enabled in the Settings, and indeed there is a piece of content there. What else might be going wrong and what can I do to make my announcement appear to students?
We have sometimes seen instances where announcements did appear for students, as you describe. The workaround was to make a small change to the announcement and re-post it. I thought there was a "known issue" article for it at one point, but I'm not finding it now...