I tried to offer a new game, rated 15+15, sides chosen randomly via the custom function. This returns a page with only the following in Chrome:
{"ok":true,"hook":{"id":"pVktGVOO"}}
...And this (screenshot) in Firefox:
http://www.tjswoboda.com/Lichess.jpg
{"ok":true,"hook":{"id":"pVktGVOO"}}
...And this (screenshot) in Firefox:
http://www.tjswoboda.com/Lichess.jpg