Is it possible to animate the opacity of a grease pencil layer?

Question

I'm trying to have a grease pencil fade in and out over a number of frames. I'm able to get this behaviour in the blender viewport, but not when I render. I've created a minimal example which is available here:

The minimal example has a grey square, drawn in the default "Lines" layer of the default "Stroke" grease pencil. The opacity of this layer is set to transition from 1 at the start to around 0.1 at the end. When I play in the blender viewport, I see a smooth transition. When I hit "render animation", I see no change in opacity for different frames, and the rendered opacity matches whichever frame I have selected in the UI. "Render animation" will still correctly render motion, if I add location keyframes, but the opacity still behaves in the described manner.

Is there a way to make the render output respect the transition between opacity values?

Steps to create the minimal example:

1. Draw a square in a new 2D animation
2. Set end frame to 20 in the timeline
3. Create a keyframe for the opacity property of the "Lines" layer, at frame 0
4. Create another keyframe for the opacity property of the "Lines" layer, at frame 20
5. In the graph editor, drag the opacity at frame 20 down to around 0.1

Answer 1

This appears to have been a bug in blender 2.81. The example above behaves as expected in blender 2.82.