Color and style of custom shape changed upon use

[pisacou]

Hello,
I am using Visio Professional in Office 365 and have an issue when using custom shapes. When I drag the shapes into a new document, the line color and style sometimes changes. E. g. a custom polygon shape with a custom dark green outline gets a black outline after it has been dragged into a new document. When I edit the master shape and set the color and style of the outline of the master shape explicitly, the problem goes away, and the custom shape keeps the correct color when dragged in a new document, until I reload the stencil with the custom shape. The stencil was saved before the reload.
What works (of course) is when I drag a custom shape in a document, select the shape with the wrong black outline color, and change the outline color to the greenish color of the original master shape. However, that only works when all lines in a custom shape have the same color and weight, and what I will need in the very near future are more complex custom shapes with different line colors, styles.


Is there a reliable way to to keep all colors and styles of a custom shape after it has been dragged into a document? What am I doing wrong?