Just to say that I too have been running into this issue.
Image in InDesign CC set to 100% transparency with normal blending mode (flattened B+W TIFF image) is being displayed as 32% multiply when opened from an IDML file.
Just to say that I too have been running into this issue.
Image in InDesign CC set to 100% transparency with normal blending mode (flattened B+W TIFF image) is being displayed as 32% multiply when opened from an IDML file.