"Unreal Packaging Issue" | Author: Antony Castro | Posted on: July 11, 2025

This week, as I pushed towards getting a playable build of "Operation Nightfall" ready for internal testing, I hit a frustrating roadblock: the project simply refused to package for Windows. Every attempt ended with a cryptic error message in the logs: "Unable to bind delegate to 'OnTargetPerceptionUpdated' (function might not be marked as a UFUNCTION or object may be pending kill)." If the game can't be packaged, it can't be distributed, meaning no one can play it. 

After a bit of digging into the call stack provided by the packaging error, the culprit was identified in my AAIC_CodeEnemyController class, specifically within its constructor where I was setting up the UAIPerceptionComponent. The OnTargetPerceptionUpdated function, which is designed to be a callback for when my AI senses something, was dynamically bound to the perception component's delegate.

The core issue was surprisingly simple: the OnTargetPerceptionUpdated function, while correctly implemented, was missing the UFUNCTION() macro in its declaration within the AIC_CodeEnemyController.h header file. Unreal Engine's reflection system, which allows C++ code to be exposed to Blueprints and enables features like delegate binding, relies heavily on this macro. Without it, the engine couldn't properly register and bind the function during the cooking (packaging) process, leading to the "IsBound() ensure condition failed" error.

The solution was straightforward: I simply added UFUNCTION() above the OnTargetPerceptionUpdated function declaration in AIC_CodeEnemyController.h. After recompiling the C++ code and addressing a few lingering Blueprint compilation warnings (which often surface after C++ changes), the project packaged successfully.

At the moment I did take any captures or video or the issue but I got the Perforce history with the changes I did: