DR17 - No more alpha layers for compound clips?

I'm not sure if this has been mentioned yet, at least I didn't find any reportings regarding this behaviour of DR17.
I have brought over some projects from DR16 and every compound clip is now handled as a solid object. The alpha layer does not get transferred though the compound clip.
I have to change the composite mode to "add". This way it works as expected.
But this workaround doesn't work, if I have lets say another PNG or compound clip with alpha between the top compound layer and the footage.
Is this a bug or does DR17 handle alpha layers from compound clips differently then DR16?
I have brought over some projects from DR16 and every compound clip is now handled as a solid object. The alpha layer does not get transferred though the compound clip.
I have to change the composite mode to "add". This way it works as expected.
But this workaround doesn't work, if I have lets say another PNG or compound clip with alpha between the top compound layer and the footage.
Is this a bug or does DR17 handle alpha layers from compound clips differently then DR16?