When only 3 rows in data sets, scatter plots uses grey-scale colors.

[cammil]

4 or more rows appears to use the expected color palette. However 3 uses unexpected black-grey-white colours for the points.

[mmagnuski]

Are you referring to a specific seaborn plotting function?
Generally - matplotlib's scatter can act weird with 3 points - RGB values are interpreted as colormap values. The documentation of scatter says that color would be read as rgb (not as colormap values) if it is a 2d numpy array (1 by 3). Unfortunatelly I've had problems with 1 by 3 too. Only when I passed a 3 by 3 (the same rgb vavlues for each observation) it worked well.

[cammil]

I checked with lmplot, regplot and pairplot (off diagonal plots). They all produced 3 dots which were white, grey and black.

[mwaskom]

Duplicate of #840