是的，介词后面一般不接形容词，但有例外，其中你说的 far from 就是其中之一，这类用法通常可以理解为其后省略了动名词 being。如：

The merger is still far from being a done deal. 此次合并还远未成事。

Teachers are far from (being) complacent about this problem. 老师们对待这个问题绝非自满无忧。

Eric was far from (being) sure and Marion looked doubtful. 埃里克根本没有把握，玛瑞恩看上去也很疑惑。