Error saying Midtones effect requires GPU acceleration on Macbook Pro M1

Great that you figured it out. So now you're able to apply Midtones? If so, it would mean that the BorisFX BCC+ caused the timeline to be rendered in the software mode (the fall-back).

Hi, Could you let us know the details of your M1 machine, the OS and the Premiere project? The media used (resolution, format and duration), the timeiline size, effects used and the general arrangement?

I ask this because we expect this message to come up only when you are using CPU/software rendering, and that is not a UI option anymore in the latest Beta builds. The only way this state can be reached, that we are aware of, is if the GPU is exhausted in some way, and the processing falls-back to software mode. If that is what happened in your case, this message is presented as designed - and if your project complexity helps us udnerstand if it is indeed so; but if not, we are interested to know how this happened on your setup.

The project file, with the media, if possible will help us immensely in replicating this in house for us to determine the goings on.