blending modes have suddenly stopped working. When i try use a blend mode on a layer it just doesnt register. When i use a PSD as a comp it doesnt read any of the blend modes. I have just updated to MacOS Big Sur 11.3.1, not sure if this might be why.
Check your hardware acceleration settings. This stuff not working right is the most common cause for blending modes also not working. Revert to software-only rendering if need be. That said, of course there could be specific other issues like you having used certain PS wizardry that AE simply doesn't support, but without any info about the document, actual belnding modes, layer styles/ layer belnding options and so on nobody can tell that, either.