Is it normal that lucid dreams sometimes feel a lot less vivid when you recall them in the morning?
I had a lucid dream last night and I clearly remember how amazed I was of its realism, and how I went around and explored - but when I woke up it suddenly seemed a lot less vivid, and now I almost doubt it was vivid at all despite remembering how impressed I was of its realism. 
Your dream probably was very vivid, but we typically don’t recall our dreams with the same amount of detail as they really had. So to answer your question, I guess it is normal for dreams to seem to be of a lesser quality after you wake up and recall them. To retain the greatest amount of detail you need to keep training your dream recall skills and you should write your dreams immediately after waking up.
Unfortunately, it is normal that dream recall is less vivid than the actual dream. On the other hand, keeping up your recall is definitely helpful to ensuring you remember the dreams. Some people will even forget they had a lucid dream!