Why mapshow is too slow in matlab r2019b?

I am running the following code to make land mask with mapping toolbox ussing ghssg data

lonlims = [-120, -75]; latlims = [0, 33];

S = gshhs('gshhs_f.b', latlims, lonlims);

nvs = [S.Level];

Sn = S(nvs~=2);

Longs = cell2mat({Sn.Lon})';

Latgs = cell2mat({Sn.Lat})';

[Latgs, Longs] = maptrimp(Latgs, Longs, latlims, lonlims);

mapshow(Longs, Latgs, 'DisplayType', 'polygon', 'FaceColor', [0.5, 0.5, 0.5])

I am running the following code to make land mask, see the map.

Since matlab version 2017b the time to plot the map has been increasing continuously. For example in version 2017a it used to take no more than 3 seconds. On version 2018b takes between 5-6 seconds. On version 2019b takes more than 2000 seconds.

I made a profile for both, 2018b and 2019b, see results in images.

Any idea whats is happening?

[Daniel Holstein]

This question has gona a long time without an answer. I, too, am having trouble with Matlab's Mapshow. It is far faster to plot each polygon individually in a loop than to use mapshow at all.

[Oliver Chikumbo]

Getting the same problem even on R2022b and it is so frustrating ... MathWorks need to respond promptly and fix this problem with mapshow