TUI: "The application panicked (crashed)" + "byte index 64 is not a char boundary; it is inside '\u{202f}' (bytes 63..66)" while composing prompt

What version of Codex is running?

0.30.0

Which model were you using?

gpt-oss

What platform is your computer?

amd64 ilnux , ubuntu 24 server via ssh from macbook terminal

What steps can reproduce the bug?

don't know how to re-produce... happened sporadicaly while back-arrowing and modifying an earlier part being composed in the TUI

What is the expected behavior?

using arrow keys, backspace, and inserting characters - typical prompt composition.

What do you see instead?

codex panics and exits to the shell

from the shell ( before running anything else after the panic exit), i checked the exit code, which was "101" :

shell> echo $?
101
shell>echo $LANG
en_US.UTF-8

Additional information

this was not editing a previously submitted prompt from the session history. this was preparing a new prompt at a new head of the history.

the part of the prompt being edited had some dash and quote characters that i copied and pasted from the agent's previous output ( I wanted to reference something it said verbatim to add clarification to an ongoing planning discussion ).

I wonder if our burst-paste processing and sync with the cursor is tripping up on byte-based editor tracking rather than character/glyph processing ( like, maybe the previous output from codex that i pasted back in were multi-byte utf8 glyphs ? the error message referrences a byte sequence that utf8 would map as a Narrow No-Break Space glyph ).

additional detail form TUI log:

ERROR panic: panicked at tui/src/bottom_pane/textarea.rs:144:28: