UserAgent: Mozilla/5.0 (X11; CrOS x86_64 8530.96.0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/53.0.2785.154 Safari/537.36

Steps to reproduce the problem:
Today I updated the External Signature extension. The only change was an if to avoid a NPE and an increase in the version in the manifest file. Now Chrome says the extension requires new permissions and has disabled the extension. The supposedly new permission is to "read and change your data on mail.google.com", but it has always had that permission.

https://chrome.google.com/webstore/a/google.com/detail/external-signature/ecikdmbcjggkblmilogmjfhemkoidacf

What is the expected behavior?
The extension should update silently without being disabled or require new permissions.

What went wrong?
Chrome disabled the extension and says it requires new permissions.

Did this work before? N/A 

Does this work in other browsers? Yes

Chrome version: 53.0.2785.154  Channel: stable
OS Version: 8530.96.0
Flash Version: Shockwave Flash 23.0 r0