Apps for reminders and calenders aren't reliable! Doens't show notifications (SlimKat)

[arly455]

I have a custom ROM on my galaxy s3 (Slimkat) and I use a lot of reminder apps like Todo Reminder and Awoken. the problem is their reminders aren't reliable. sometimes there aren't any reminders a whole day in Todo Reminder, and when I open the app all the previous unopened reminders are popping up.
This is terrible! I can't rely on my reminders that it will surely be there. It's like the reminder apps don't open in the background. Maybe it's something with the task killer?
What do you think?

 

[Golfdriver97]

Do you use a task killer? If so, it is probably killing your app which may need to be opened in order to finish the process of reminding you.