Without being able to open the file in Illustrator, it is difficult to make a statement.
Maybe the paths are not closed?
I appreciate your help on this.
I checked again. You are right
I was really negligent: " paths are not closed ".
could you please explain what means "paths are not closed"?
A closed path is a group of single lines (straight lines or curves) satisfies the following conditions: the last anchor point of this single line is the first anchor point of the next single line ( about coordinates XY ), and the last anchor point (of the last single line) coincides with the first anchor point of the first single line.
The rest is the path not closed.
My case is that the last anchor point (of a curve) did not coincide with the first anchor point of the next curve.