Fork won't release the lock on the original conversation

What version of Codex CLI is running?

0.155.0

What subscription do you have?

API user

Which model were you using?

5.6 sol

What platform is your computer?

linux

What terminal emulator and version are you using (if applicable)?

Terminal

Codex doctor report

What issue are you seeing?

When forking a conversation, the session would lock both new and old conversation. so if I create a new terminal and resume the old conversation, it would suggest the old conversation is locked.
If I exit the codex from the terminal that runs the forked conversation, the new terminal that try to resume old conversation would also unblocked.

What steps can reproduce the bug?

start a conversation in terminal A, talk something, and try to fork the conversation. keep this terminal open then start a new terminal and do codex resume and pick the original conversion. it would not allow you continue and suggest this conversation is locked.

What is the expected behavior?

Fork should release the conversation so that I can have another terminal keeps the original conversion.
Otherwise, now I have to kill the forked session and resume both terminal. It's very painful and make fork not usable.
Another work around maybe allow it to create a new terminal with new conversion when triggering fork.

Additional information

No response

Reproduce the fork and resume flow described: keep the forked session open in terminal A, then try to resume the original conversation in terminal B. Start by tracing the conversation-lock handling around fork and resume. Done means the original conversation can be resumed while the forked session remains open, without requiring the forked session to exit.