Duplicate character gets inserted

• I am on the latest Hyper.app version
• I have searched the issues of this repo and believe that this is not a duplicate

• OS version and name: macOS Mojave 10.14.3
• Hyper.app version: 2.1.2
• Link of a Gist with the contents of your .hyper.js: https://gist.github.com/kanbara/ddfc30d1df77a34ed3bb1b84f2d51e1a
• Relevant information from devtools (CMD+ALT+I on macOS, CTRL+SHIFT+I elsewhere): N/A
• The issue is reproducible in vanilla Hyper.app: Issue also occurs on plain hyper.app

Issue

If I type cd and use tab completion (fish shell 3.0.0), and backspace ,the last c does not get removed. If I type cd ~ then I get another ~ randomly. The cursor is advanced but the character does not actually affect the input. It leads to visual glitches at the beginning or middle of a command which is quite annoying.

See asciinema https://asciinema.org/a/WOfCwDqip7tXPPEtvSiy5FxvL

Reproduce the issue in Hyper.app 2.1.2 on macOS with fish 3.0.0, using the cd and cd ~ tab-completion cases described in the report. Compare the terminal's displayed input and cursor position after backspacing or repeated completion; done means these actions no longer leave duplicate characters, visual glitches, or an incorrectly advanced cursor.