I see many others are having this problem, but none of the threads so far is helping me to understand a work-around here. I have different composite layers set to "Hard Light" and adjusted opacity levels over all of my main clips in the timeline. I now need to add transitions between each one of my clips and I'm using an ink transition I downloaded. I can't compound the two layers because when doing that, I'm not able to add the transition because essentially, I've created a new clip, and there is no video "beyond the end of the clip" to create the transition. I also don't want to shorten all of these clips. So, I tried adding the transition to the main clips and then also adding the same one to the composite clips above them. Now, the second the transition starts, the opacity seems to change to 100% through the whole transition. How do I work around this? Here's shots of the timeline, and then how it looks just before the transition and just after it starts. Thanks!
Whether it's a limitation set by FCPX (and other NLEs) or just a fundamental limitation I'm not sure, but when you apply Hard Light you're mixing one color/luma with another. It's not really any transparency. So when you try to do a transition between layers with blend modes you get strange results. It might the order of operations or something. But the dissolve is affecting transparency of 4 layers in your shot, and those 4 layers are also being combined with Hard Light mode. So the opacity of the dissolve is also changing the way hard light interacts. You need to bake in the order of operations by compounding layers together and then dissolving them. If you don't have enough media to do that, then you also don't have enough media to do a dissolve. Remove the dissolve. Compound them. Then open the compound and lengthen the layers the amount needed. Or lengthen the layers before making the compound. Up to you.