Plotting Geology Fault problem (pen attribute solid line style overide from segment header)

Dear all,

I am using GMT 6.4.0 modern mode, trying to plot fault line in several line style by overriding on every line segment header as seen on file below

0 4
4 4
< -Sf+0.24i+l+t -Wfaint,gray,-
0 3.5
4 3.5
< -Sf+0.24i+l+t -Wfaint,red,.-.
0 3
4 3
< -Wfaint,blue,solid
0 2.5
4 2.5
< -Sf-1c/0.5c+r+s+p1p,solid -Wfaint,-
0 2
4 2
< -Sf-1i/0.5c+l+s+pfaint,red,solid -Wfaint,.-.
0 1.5
4 1.5
< -Sf+0.24i+l+t+pfaint,red,solid -Wfaint,solid
0 1
4 1
(line segment header symbol is inverted)

with the script:

gmt begin fault_line_style png
gmt plot line -Jx2.5c -Sf+0.24i+l+t -Gblack -Wfaint,4_1 -Baf
gmt end

The line style changes for the first 4 lines (figure attached) just fine, the line style overide -W could change the line segment from dashed line into solid line (blue fault line). The line style also can be change into other dashed line (i.e. .-.)

The problem comes when the segment style overide of -Sf is used with the flag +p . In the plotted line on the bottom the pen style overide -Wfaint,solid failed to change the line style into solid line instead using the -W parameter from previous segment header for the line style -W and the symbol front outline -+p (in this case using “dot dash dot”)

Is this a bug?

Thanks a lot to anyone who can help me…