Where's the evidence that 1024kb's issue had anything to do with bw? How is that vaguely recalled anecdote a trust issue with bw? It was probably caused by accidentally copying something to the clipboard or some other buffer which was then transferred via ssh and imported into weechat, possibly with the help of custom terminal, ssh, tmux, or weechat settings making it too easy for data to be slung around like that.

I can't think of a plausible explanation for how bw is at fault for its terminal output ending up, across a ssh session and tmux invocation, in the chat history of weechat. Even if bw auto-copied its output to the clipboard (which as far as I could tell by glancing at the cli options, it doesn't and can't), and the clipboard is auto-copied to remote hosts, clipboard contents shouldn't appear in an irc client's history without explicit hacking to do that.

The claim is just noise, particularly because it doesn't seem to have ever been investigated.

It seems prudent, if someone wants to use a cli, to use rbw rather than bw, or even just pass or keypassxc-cli (and self-managed cloud backup or syncing). However, that's based on bw being a javascript mess, not based on the unlikely event of bw injecting its output through ssh into irc clients.