[Bug] Prompt injection from sub-agent with no tool usage consuming excessive tokens

Bug Description
I has received a prompt injection from a sub agent. it cannot tell where it came from, the subagent consume 18K tokens but use 0 tools ????

Environment Info

• Platform: linux
• Terminal: Orca
• Version: 2.1.198
• Feedback ID: 197aa6ea-568a-4e09-a8fe-dd06889a3db2

<img width="810" height="598" alt="Image" src="https://github.com/user-attachments/assets/28cb37e4-da53-4fa4-97c7-6c343a37ec57" />

<img width="860" height="122" alt="Image" src="https://github.com/user-attachments/assets/e40d04c8-e139-4111-aa8e-8787ee944c97" />