How come my effect strip doesn't render?

I have a Gaussian Blur effect strip that shows up properly in the Preview window but then fails to render. Why is this happening?!

You maybe trying to render all including 3d stuff or compositing, it is best to do a viewport render animation, which will only render vse

Thanks for the reply. It’s definitely the case that under view -> Sequence Render Animation, the render result is correct. However how do I export the image sequence instead of just previewing it? Thanks.

what ever settings you have in render output settings blender will use, so if you have a png for output it will use that.

I found something that might be a bug. So as you can see in the screenshot I’ve set Size X and Y Values for the Gaussian blur. But if I hit F12 to render a frame from the animation where the blurring should apply, and then mouse over the effect strip window, the values that were at 20 immediately jump to 0. But what’s weird is if I set the values back to 20 as the animation is rendering, I can get the blur effect to work.

Why is this happening? Is this a weird bug?