If you have a Garmin chart plotter read this service advisory:
"Garmin is aware of the following issue that affects US coastal and Great Lakes chartplotter customers using 2018.0 or 2018.5 charts released in November 2017 and May 2018, respectively: With the chartplotters navaid type set to NOAA, the buoy top marks draw over the green starboard buoy rectangles and red port buoy triangles, obscuring the red triangles, as shown below. This issue is most prevalent in the Intracoastal Waterway (ICW), but can also be observed in other areas along the US coastline and Great Lakes."
https://www8.garmin.com/marine/notices/obscured_navigation_buoys.pdf
"Garmin is aware of the following issue that affects US coastal and Great Lakes chartplotter customers using 2018.0 or 2018.5 charts released in November 2017 and May 2018, respectively: With the chartplotters navaid type set to NOAA, the buoy top marks draw over the green starboard buoy rectangles and red port buoy triangles, obscuring the red triangles, as shown below. This issue is most prevalent in the Intracoastal Waterway (ICW), but can also be observed in other areas along the US coastline and Great Lakes."
https://www8.garmin.com/marine/notices/obscured_navigation_buoys.pdf