Create a new artboard doc. Select the artboard and confirm the blend mode is Pass Through.
Add another artboard. The artboard has the blend mode "Normal". Any artboards added will show the blend mode "Normal".
Save and close the doc. Reopen the doc. All artboards now have "Pass Through".
Create a new artboard doc. Select the artboard and confirm the blend mode is Pass Through. Add another artboard. The artboard has the blend mode "Normal". Any artboards added will show the blend mode "Normal".
Save and close the doc. Reopen the doc. All artboards now have "Pass Through".