Cursor has offset in tmux

With every typed character the cursor get a little offset to the left.

In this image the cursor is completely to the right.

I thought the problem was tmux, but it exists without tmux and over ssh, too.

The report names no source file, test, or entry point. Start by reproducing the cursor offset while typing both with and without tmux, including over SSH, and compare the terminal rendering with the attached image. Done means the cursor stays aligned with the typed text in each reported environment.

Written by the indexing model from the issue text.