adk web does not show the message from a2a agent when the part contains the file

[nguoithichkhampha]

Describe the Bug:
adk web UI show the empty block when display the message from a2a agent. The message contains both Part(text) and Part(File)

Steps to Reproduce:
Please provide a numbered list of steps to reproduce the behavior:

1. Connect a2a agent to adk framework by using class RemoteA2aAgent
2. Run the query and a2a agent response have both the text and file

Expected Behavior:
adk web UI show text normally include the block for the file info

Observed Behavior:
adk web show empty block

Environment Details:

• ADK Library Version 2.2.0
• Desktop OS: MacOS
• Python Version : 3.12

Model Information:

• Are you using LiteLLM: No
• Which model is being used: gemini 3.5 flash

---

🟡 Optional Information

Providing this information greatly speeds up the resolution process.

Logs:
I added the log message inside the function convert_a2a_part_to_genai_part
text file.

2026-06-25 14:38:41,131 - DEBUG - part_converter.py:75 - Converting A2A FileWithUri to GenAI Part with uri: https://storage.googleapis.com/emotiv-agent-generated-image/test1/63ecccd8-a9b0-4701-9c7f-5417a6a991dd/002be84a-1236-4123-9090-30076cac492d_signal_quality.png, mime_type: image/png, name: 002be84a-1236-4123-9090-30076cac492d_signal_quality.png

Screenshots / Video:
when a2a agent send the file part + text part

when a2a agent only send text part

How often has this issue occurred?:

• Always (100%)

[nguoithichkhampha]

Update:
seems, there is duplication in Part of adk. I see, 2 file part even a2a agent only send one

{"parts":[{"text":"For context:"},{"text":"[eeg_research_agent] said: I have processed the signal quality for your recording session. \n\n### **Signal Quality Analysis"}],"role":"user"}
{"parts":[{"text":"For context:"},{"file_data":{"display_name":"002be84a-1236-4123-9090-30076cac492d_signal_quality.png","file_uri":"https://storage.googleapis.com/emotiv-agent-generated-image/test1/2ec66f1c-92f2-478f-b098-db5a76b64358/002be84a-1236-4123-9090-30076cac492d_signal_quality.png","mime_type":"image/png"}}],"role":"user"}
{"parts":[{"text":"For context:"},{"file_data":{"display_name":"002be84a-1236-4123-9090-30076cac492d_signal_quality.png","file_uri":"https://storage.googleapis.com/emotiv-agent-generated-image/test1/2ec66f1c-92f2-478f-b098-db5a76b64358/002be84a-1236-4123-9090-30076cac492d_signal_quality.png","mime_type":"image/png"}}],"role":"user"}
{"parts":[{"text":"For context:"},{"text":"[eeg_research_agent] said: Antigravity agent completed."}],"role":"user"}
{"parts":[{"text":"Can you process the eeg channels ?"}],"role":"user"}

another issue, when the error happens, I can not continue the conversation