Summary
In a new project created from the First Person template (Arena Shooter variant), pressing Play in Lvl_ArenaShooter produces repeated Blueprint runtime errors from /Game/Variant_Shooter/Blueprints/AI/StateTree/StateTreeTask_SenseEnemies:
“Accessed None trying to read property Controller”
The errors occur on the Bind/Unbind Event to On Target Perception Updated and On Target Perception Forgotten nodes, for every AI controller in the level (BP_ShooterAIController_C_0 and _C_1). The task’s Controller reference is never valid, so the AI perception delegates are never bound. The issue has been present since 5.7 and is still reproducible in 5.8.3.
What Type of Bug are you experiencing?
AI
Steps to Reproduce
- Create a new Blueprint project from the First Person template, Arena Shooter variant.
- Open Content/Variant_Shooter/Lvl_ArenaShooter.
- Press Play In Editor without making any changes.
- Open the Message Log or Output Log.
Expected Result
The level runs without Blueprint runtime errors, and the AI enemies bind to their perception events to detect the player.
Observed Result
Blueprint runtime errors are logged for every AI controller in the level (BP_ShooterAIController_C_0 and BP_ShooterAIController_C_1):
“Accessed None trying to read property Controller in /Game/Variant_Shooter/Blueprints/AI/StateTree/StateTreeTask_SenseEnemies.StateTreeTask_SenseEnemies_C”
Function: ExecuteUbergraph_StateTreeTask_SenseEnemies
Failing nodes (EventGraph):
- Bind Event to On Target Perception Updated
- Bind Event to On Target Perception Forgotten
- Unbind Event from On Target Perception Updated
- Unbind Event from On Target Perception Forgotten
The errors appear when the task enters its state (Bind) and again when it exits (Unbind).
On ending PIE, the log also shows:
- LogStateTree: Warning: Context Requirements in UStateTreeComponent::StopLogic failed. Component tick is disabled. (x2)
- LogCrowdFollowing: Warning: Unable to find RecastNavMesh instance while trying to create UCrowdManager instance
Additionally, loading Lvl_ArenaShooter reports two missing template assets:
- /Game/LevelPrototyping/Interactable/Door/Assets/Meshes/SM_DoorFrame_Edge
- /Game/DemoTemplate/_Core/MI_Intro_Colorway (referenced by BP_WobbleTarget)
Affects Versions
5.8
5.7
Platform(s)
Windows
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Additional Notes
Engine: 5.8.3-58210709 (Launcher build)
OS: Windows 11 26H2 (10.0.26300)
CPU: AMD Ryzen 7 7700X
GPU: NVIDIA GeForce RTX 4060, driver 617.14
RHI: D3D12, SM6
Reproducibility: always, on a freshly created project with no modifications. The same errors were already present in 5.7.
The full Output Log is available on request (text files cannot be attached here).