Error when editing: Uncaught TypeError: Cannot call method 'transform' of undefined

[danwinkler]

To reproduce: (can reproduce at http://ot.substance.io/demo/)

1. Go to page, clear all text from editor, close window.
2. Open page in two windows (with Chrome inspector or other tool open).
3. Type one character (I used "a") in editor in one window
4. Type one character in editor in other window.
5. Error is thrown

Sometimes if you keep typing the following error is thrown many times:

Uncaught Error: Both operations have to have the same base length

From the user perspective, there appears to be no issue. Maybe it's not actually worth fixing?