I've been having this problem with automation for quite a while now. I'm using version 1.2.1. for reference. I can only add points in the grid (if thats what its called?) at 1 and 0, and it only happens when using an effect. I've done it using volume and its worked fine, and iirc when I first tested it out using an effect it worked perfectly, but I was only testing automation out for the first time on a project I wasn't quite sure I wanted it on, so I don't have that project in particular.
I made a video showing this problem in case my description was not fantastic (apologies for the unedited footage lol):
https://youtu.be/Z8Ut7XVVcEI
I made a video showing this problem in case my description was not fantastic (apologies for the unedited footage lol):
https://youtu.be/Z8Ut7XVVcEI