Font Update broken after update to 4.1.27

Hi all,

after I updated the Redux plugin to 4.1.27, the font-update in the typography settings of the theme we use stopped working.

Pressing the ‘one-time update’ in:

Your Google Fonts are out of date. In order to update them you must register for Redux to enable updates. Run a one-time update.

Results in a

Update Failed: "function(){return u(n),r.apply(this,arguments)}". Retry?

In the Browser console, there is a POST to .../admin-ajax.php with the form data:

action=redux_update_google_fonts&nonce=<some_numbers_and_letters>&data=manual`

with a resulting 500 Server Error.

The page I need help with: [log in to see the link]