Data is stored in the wrong session when multiple sessions are running #20552

Description

I had a session running in Build mode and went and opened a new session in Plan mode. As they were running, data from the Build session started showing up in the Plan session.

You can see that my Plan session (consisting of only 1 prompt) shows that it edited files:

The review tab for both sessions displays identical changes, in both "Last Turn" and "Session" changes modes.

However, this isn't isolated to a UI problem. I used the event stream to confirm that the PATCH parts were in fact getting sent to messages in the Plan session. I then double checked the opencode.db sqlite file directly and confirmed that the Plan session did in fact have stored patch parts.

Plan Session ID: ses_2b54c85c5ffejvxUwZT2t1ffuc

Patch parts:

Messages with the Patch parts + the message from parentID showing mode is set to plan

I don't see any "read" nor "write" tool parts in the Plan session corresponding to the files it says it patched so it might be isolated to the PATCH parts.

I don't know if those parts are contributing to the Message's token counts and inflating the stats since the Messages do also have real parts in them alongside the incorrect PATCH parts.

Plugins

No response

OpenCode version

v1.3.13

Steps to reproduce

Not sure if this is relevant, but I'm running opencode web in the terminal and then having OpenCode Desktop connect to that port. Then just run 2 sessions in 1 project in the same workspace.

Screenshot and/or share link

No response

Operating System

macOS 26.3.1

Terminal

iTerm 2