Transparency applied on top layer affecting layers that are drawn under - ArcMap 10.5

[Kolek]

Hello,

I am having some issues with symbol transparency in ArcMap 10.5.

Set the yellow point layer transparency to 30% --> When exporting it to PDF all the line features below that layer become lighter in colour (2nd picture) . Any suggestion why is that?  (Transparency was only applied to the point layer)

 -->Original (no transparency)

--->30% transparency applied to yellow point layer only

Thanks,

[DuncanHornby]

May be related to this bug?