I'm pretty new and just following some tutorial. Got that problem I can't get solved even after reading docs.
I did a 30sec movie (rendered to .png). Now I put this into Blenders Video Editor and switch to Compositing (activating 'Use Nodes'). There is the problem: no matter which filter I'm adding (Lens Distortion, VHS) it just won't render. It shows in the preview ('Viewer' Node) but it won't render.
Using Blender 3.6 because on Blender 4 there's no 'Denoiser' for my Debian system.