Oh good. Another mystery solved.
As for Skin of Evil airing before Symbiosis, I always love the little wave Denise Crosby gave in the background in her real final scene.
And also, it's not like I haven't seen the episodes several times; I know what's going on, even in the wrong order.
And also, I've got TNG HD on Sky+, so I record them and watch them in whatever order I see fit.