You don't say which chart you are referring to, but as I have never seen this in a chart of commercial
origin, I suppose you must refer to a privately converted chart.
If notes, as for example tidal information, behaves the way you describe, it is due to the way the person who converted the chart placed the so called PLY points. I'm surprised to see charts
where essential information is excluded in this way, the cartographer put it there for a reason.
If you know libbsb this can, however, easily be corrected.
More about this in the chart thread.