Signposts only appear when the objects themselves are hidden. If you can see the chord symbols (as in your screen shot) you don’t get signposts as well.
This applies to all signposts, not just chord symbols.
As a followup: I removed everything but the solo vocal instrument from the current Layout. So no chord symbols are visible. I’m still not seeing the chord symbol signposts.
Another layout of another flow in the same Project is similar: only the solo vocal is displayed. But in that case, chord symbol signposts do show up. I’m not sure what’s different between the two.