WowAce

What steps will reproduce the problem?
1. Play the game with notifications for debuffs enabled
2. The error may possibly be related to the "blink" effect on notifiers, but I have not tested this extensively enough.

What is the expected output? What do you see instead?
Expected output is for the add-on to run smoothly. Instead it often generates LUA errors that occasionally slow down the game significantly.

What Grid2 version and language of WoW are you using?
revision 731, English WoW 6.0.2

Do you have an error log of what happened?
Yes, I am attaching it to this ticket.

Please provide any additional information below.
Grid2 is trying to index a nil object. I am attaching a patch that avoids the error, which seemingly also remedies any performance issues it could cause, but it is not a true fix (the real error is somewhere deeper in the code).