When I unlock Achievments, on Singleplayer and Multiplayer, the achievment unlocking notification appears approx 30 - 60secs after completing the Achievment.
As you can see in the video below, the achievment is 'apparently' unlocked when I am in the achievment menu, when I am not doing anything. I couldn't include me doing the achievment in the video as my device only lets me record videos that last for 30 secs and below.
Steps to Reproduce:
1. Try to unlock achievment that isn't already unlocked
2. Notice that achievment notification shows up 30 - 60secs later.
Expected Result:
Notification shows as soon as you have done the required thing to unlock the achievment.
This can make me think that I have already unlocked certain achievments when I haven't
Attachments
Comments 5

You should be receiving the "toast popup" when you earn an achievement. However, these are sent from the Xbox Live network, which is often very busy so the popup can be delayed or even dropped. This is an issue with Xbox Live, not the game, so we can't do anything about it on the bug tracker. If you want to pursue it, please contact Xbox Support.
Quick Links:
📓 Issue Guidelines – 💬 Community Support – 📧 Customer Support – 📖 Game Wiki
You should be receiving the "toast popup" when you earn an achievement. However, these are sent from the Xbox Live network, which is often very busy so the popup can be delayed or even dropped. This is an issue with Xbox Live, not the game, so we can't do anything about it on the bug tracker. If you want to pursue it, please contact Xbox Support.
Quick Links:
📓 Issue Guidelines – 💬 Community Support – 📧 Customer Support – 📖 Game Wiki