Mods that do Reagent tracking or Disenchant Predicting are suffering from such issues as well. Example being Fizzwidgets Disenchant Predictor. New shards were added and he tries to hook the Tooltip Frame to update it. A lot of these error happen when a mod has some tie to a frame display and whether or not you are in combat can affect it. Again this all mostly because of the new secure frame system and the fact that Blizzard basically locks 90% of the interface while in combat. I would check with the DE'er and see if they run anything that helps with reagent tracking or dis/enchanting.

Alrighty, I think I have figured out what's wrong here:

I read up on this thread here, which describes how "tainting" and the secure blizzard functions work.

In short, I'm hooking the "chat frame" function ChatFrame_OnEvent, for the purposes of capturing incoming whispers (!dkp Chops) and hiding the output so as to not spam the mod user.

Because I'm hooking that with a user-defined function, any other functions that are called along the way for processing that particular event are then made "Tainted" as well, thus producing the "Blizzard UI Secure Function" Error message you're seeing.

I tried using the suggested "hooksecurefunc" function to hook that particular function, but the way that "hooksecurefunc" works, by running my code after it runs the blizzard code, it defeats the purpose of hooking the function in the first place (which is to hide the messages from the user).

At this point, we're faced with two options:
1) Put up with the occasional error messages and hope for blizzard to modify this functionality (unlikely), or
2) Make the incoming messages viewable again.

Neither are good choices, but architecturally, I don't think that what I'm trying to accomplish is possible anymore.

Here's my post to the UI forums. Hopefully there's an answer for us that'll be pleasing to us.