I don't know then. Sorry. I just got lucky with trying that I guess. Maybe try going and doing more stuff before u go back to Arnie's than just the date?
I was having the same problem. I was able to fix mine by just leaving Arnie's office instead of clicking on him again when I loaded up the game. I then went to taco bandito and called my chick's boyfriend to go on a date there. After the date was over Arnie called again. I went to his office again and it was fixed! Hope…