Well as far as things in my dreams go my dreams remain pretty stable I guess. The setting will occasionally change, but it kind of integrates into my dream to where I don't really notice it as out of the ordinary and I really only notice it when I'm recalling the dream for my journal.
Hmm....I guess than its probably that I'm giving too much of my attention to small details...

I'm not 100% sure what you mean by have you gotten through a lucid dream and had it remain stable the whole time.
By that I mean like no interruptions have occurred in the dream setting that stopped you from doing what you were about to do. For instance, Like when you suddenly appear in the void or the dream just collapses quickly.

For me instability is when my dream starts to fade. It's almost as if I become like disoriented in the dream. My vision will basically start to fade to black. This usually happens when I lose focus. I've found that if I'm not actively focusing in my lucid dreams they have a much higher rate of collapsing. Anyways, most of my lucid dreams end when it fades to black like that. Except I don't wake up when that happens, I'm left in sort of a WILD state. I just call it the void. I can basically feel my dream body still, but all I see is darkness. A lot of time I just use dream re-entry techniques to get back into my dream or alternatively I can start a new dream by rolling my dream body off my bed in the "void".
I consider that instability as well and have experienced the same thing before. I don't roll off my bed in the dream though. I just wait a bit until I can move freely again. If I'm in the void though I tend to be flown or fall into another dream setting.

I want to work on getting better at just imagining and entering dream scenes in this state, but haven't put too much effort towards it yet.
Oh, I'm sure you can do it if you put in the effort. :3 Also, thanks for replying. I don't really understand how some peoples lucid dreams are like even though I do read entries here so its good to know about your experience with it.