I am having an issue with the Mask stack in that on mobile devices for some pictures the bottom mask just shows as black rather than working as it should.
I have made and experimented with different sizes of pictures for mobile only and tried different height settings but it doesn’t seem to help. It works fine on desktop and tablet widths.
Didn’t hear back from you so I’m following up to get that project file download link so I can help you out.
I’ve tested Mask at the mobile breakpoint here and it is work as expected. This means I suspect there’s something specific to your use of the stack in your project.
Still suspect it is some setting in your project that you may be overlooking. Start a new project file as a test and try it out again there and see how it goes. Let us know your results.
Just to let anyone that views this post for help in the future - I had selected dark mode in the Mask setting and this is why it showed up the way it did on my phone. This was easily resolved and Adam was very helpful.