Less of a guide but more of a discussion. I have 45/46 and haven’t been able to unlock this. I’ll update this guide when I manage to get it but right now it seems like there are still problems earning this when all other achievements are unlocked. Looking for help, thanks.
Please do not downvote this solution. I’ve been in contact with Team17 support on twitter and they are looking into the issue but have had trouble recreating the issue. I’d like to provide as much information as I can here to help others in my position.