Versions:

• Firefox 50 (latest)
• jQuery 3.1.1

Thing: I have a loading bar that animates from left-to-right, then resets. Note that it uses the complete callback (from animate) to fire itself again.

Repro:

1. Load http://jsbin.com/woperab/8/edit?html,css,js,output in Firefox
2. Run, in Firefox.
3. Minimize Firefox window.
4. Wait about 2 minutes (get a cup of coffee).
5. Come back.
6. Drink coffee.
7. Square has stopped moving. Console shows: "Too much recursion".

Note that it works if I wrap the "reset" call in a setTimeout, as in:

complete: function() { setTimeout(reset, 0) }

Speculation: Probably something to do with the requestAnimationFrame changes in jQuery 3? (If you leave the window focused, the recursion error does not appear).

Does NOT happen in Chrome/IE. Also, doesn't happen with jQuery 2.1.3.