Martin,
We actually do work with most other extensions that have their own Facebook integration. However, the 'all.js' script from Facebook was deprecated and replaced over 3 years ago and is no longer recommended by Facebook to be used. The new sdk.js file, which we use, is not compatible with the old file being loaded on the site.
There's nothing we can do to support that older version as Facebook intentionally blocks them from working together.
For more details, see:
Facebook's quickstart guide which specifically calls out the sdk.js file:
developers.facebook.com/docs/javascript/quickstart
Another guide from Facebook specifically saying not to use all.js:
developers.facebook.com/docs/javascript/howto/angularjs
And, of course, the obligatory Stack Overflow post:
stackoverflow.com/questions/38462764/dif...ok-all-js-and-sdk-js
I hope that helps explain. I'd recommend contacting the Rewards extension developer to let them know, though they should already. Some extensions have options to not include the Facebook Javascript, in which case they can piggy back on our inclusion.
Thanks,
Alex