set -g extended-keys on breaks pasting multiline text — escape codes appear instead of characters

[asirago]

Issue description

When set -g extended-keys on is enabled in .tmux.conf, tmux correctly registers advanced key sequences such as and .

However, enabling this option causes pasted text to be interpreted incorrectly, instead of inserting the actual text, tmux outputs visible escape codes (e.g., ^[ [27;5;106~) corresponding to ANSI control sequences.

Expected behaviour

type Company struct {
	Name    string
	Address struct {
		City    string
		Country string
	}
}

Actual behaviour

Additional information

• tmux version (tmux 3.5a).
• Platform (Darwin arm).
• Terminal in use (Ghostty).
• $TERM inside tmux (screen-256color).
• $TERM outside tmux (xterm-ghostty).

tmux-out-72718.log
tmux-server-72718.log
tmux-client-72716.log

[asirago]

The problem started occuring with version 3.5a after upgrading with brew upgarde earlier today.

I have since gone gack to version 3.4 where it works as expected.

[nicm]

Does this still happen if you build tmux from master?