Add on not shown at the toolbar. Only working under development mode

This is my add-on https://addons.mozilla.org/addon/birchwords-dictionary/

It’s totally working fine in development mode but not in the release version.

The background script is not running and the icon is not showing.
Not knowing how to debug this.
Because it’s totally working perfectly in development mode

Works for me in Release and Nightly. But the version is 3.16, so maybe you fixed it since.