Can't find JS file after upgrading from 1.8.1 to 1.9.1

Hi all,
we’re encountering in a issue after upgrading Drone from 1.8.1 to 1.9.1, seems like Drone server is unable to find the correct app.HASH.js file.
After upgrading every page were completely white and an error shows in the browser console:
The resource from "https://drone-server/app.HASH.js" was blocked due to MIME type (“text/plain”) mismatch (X-Content-Type-Options: nosniff).

Any clue?

we are running 1.9.1 at and the website is serving the javascript file as expected. The site supports a large number of users and we have not received any reports of problems. So although I am unable to reproduce the issue, if you are able to reproduce and can send a patch we would be happy to accept.