Cursor jumps and flashes when deleting text in input field

What version of Codex CLI is running?

codex-cli 0.118.0

What subscription do you have?

free

Which model were you using?

gpt-5.4 medium

What platform is your computer?

Microsoft Windows NT 10.0.26200.0 x64

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

CMD, Antigravity terminal

What issue are you seeing?

When deleting characters in the input field, the cursor frequently jumps or changes position very rapidly. This creates a flashing effect in the UI. The issue also occurs occasionally while typing, but it is most noticeable during deletions.

What steps can reproduce the bug?

Uploaded thread: 019d3b53-4440-7a03-9fd0-013b0e9f485d
It is very difficult to capture a screenshot of this behavior because the flashing happens so quickly when deleting.

What is the expected behavior?

The cursor should consistently remain at the logical insertion point during both typing and deletion, without flashing or unexpected movement.

Additional information

_No response_