Collapse Transformation and Layer Styles (bug) AE 2017.2 Release. I'll try to be as clear as possible:


I create a comp with two text layers:

I precompose those two text layers and set Nested Comp's Opacity to 30%:

In Nested Comp I apply Bevel and Emboss to the upper text (setting Shadow's and Highlight's Opacity to 0%, so B&amp;E is effectively nonexistent):

In Containing Comp I switch Collapse Transformation On and upper text's opacity goes to 100%:

The end.


Add 1. It's not like upper text's Opacity is not affected by Nested Comp Opacity parameter. More like it becomes binary. If I set it to any value >0%, upper text will be 100%. If I set it to be 0%, upper text becomes 0%.


Add 2. In Layer Styles it's not about B&amp;E but rather Blending Options. I may delete B&amp;E and everything remains the same:


Add 3. Upper text's Opacity on the Containing Comp is not just 100%. It actually equals to the Fill Opacity parameter of Blending Options of Layer Styles of upper text in the Nested Comp:


Add 4. The whole issue disappears if a dummy Transform Effect is applied to the Nested Comp. Moreover, not only the Transform Effect may be dummy, you can actually SWITCH OFF all the effects for the Nested Comp but the very existence of that not-applied effect fixes the problem:



Due to the Add 4 I assume, it's a bug. Looking forward for your comments and explanations on how does it happen and further insights on how Collapse Transformation works and Layer Styles place in rendering hierarchy.
Thanks.
it's not a bug, it's the nature of collapse transformation switch, and when you've added this dummy effect you simply have disabled the collapse transformation.