Replying to say I've been having this issue since the Socialize Grim Reaper task first appeared, no resolution yet. I had already become friends with Grim the previous week, but during that week there was the Become Friends challenge, I completed the other challenge, and also made sure to "Become Best Friends" with Grim just to cover all bases. Since then, I've had my Sim connect with Grim over the phone, I've had Grim over as a houseguest, I've summoned Grim a few times using the Grimophone, and even made a new household member and immediately killed that Sim to summon Grim via death to check if it would be a second, separate Grim, but nothing! The subsequent week, I could see that there were new challenges when I clicked the little Grim tab on the left side of the screen, but they wouldn't populate as actual challenges I could complete, and I was still missing the 75 points I should have had from completing the befriending task the previous week, so I haven't yet been able to earn the book reward. In the meantime, no matter how much I keep gardening or being friendly with Grim, nothing changes, and unless the functionality exists and I just haven't found it, I can't try doing the whole Reaper's Rewards Challenge from scratch with a new Sim to see if that fixes it. I don't want to not be able to play the rest of the challenge/not get the rewards just because the game won't log that I have indeed completed a task from a few weeks ago! Just reporting this to add to the data on the issue, not sure if it's being looked into yet! Edited: I have many but not all packs, I have no mods, and I play on a Mac.
