\usemodule[tikz]
\setupbodyfont[40pt]
\starttext
\definecolor[mycol][c=0.23,m=0.58,y=0.88,k=0.45]
\definecolor[mycol_h][c=0.115,m=0.29,y=0.44,k=0.225]
\definecolor[mycol_q][c=0.055,m=0.145,y=0.22,k=0.1125]
\startcolor[mycol]
{\bfa •••••••• Test}
\stopcolor
\starttikzpicture
\fill[mycol] (0, 0) rectangle (2,4);
\fill[mycol_h] (2, 0) rectangle ++(2,4);
\fill[mycol_q] (4, 0) rectangle ++(2,4);
\stoptikzpicture
\stoptext
I'm not so familiar with metafun, so I couldn't do the rectangle with metafun (the different colors between context/metafun and tikz would certainly be better visible so). But the bullet shows, that the text color isn't the same as the tikz-figure. But they should as they are identical. Something must have changed in color handling.
Christian