I found the solution with this answer. The only option you needed is enforceFocus.
jQuery
// Since confModal is essentially a nested modal it's enforceFocus method
// must be no-op'd or the following error results
// "Uncaught RangeError: Maximum call stack size exceeded"
// But then when the nested modal is hidden we reset modal.enforceFocus
$.fn.modal.Constructor.prototype.enforceFocus = function() {};