Last summer I had trouble on the first night at only 10700 ft. Worst elevation sickness I've ever felt. Was having some neurological symptoms, like hardly being able to stand or walk a few feet without stumbling, difficulty holding or handling things, very slow thinking and loss of a lot of vocabulary, as well as some of the usual fun stuff like losing all my dinner, horrible headache and nausea, of course. We almost pulled the plug in the middle of the night and went down, but I seemed to stabilize, though due to nausea I couldn't lie down, had to sleep propped up against a rock.
Next day made the pass (12K) and then descended below 9K for night 2. Night 3 after an easy day was just under 10K. Then another pass (Muir-a bit over 12K) and a longish day for me though pretty reasonable, camping at about 10700 again where I again had similar, though not quite as severe symptoms. This really threw my confidence, as I have never, ever had any issues after the first night, and I was feeling close to as sick again as on the first night. Horrible headache & nausea, loss of strength and motor control, difficulty thinking and doing much of anything, debilitating fatigue, etc. Again slept propped against a rock.
My doc said I'd probably had some HACE the first night and that once you have it, it can take a long time to recover, that the 4th night issues were due to damage on the first night. I'm hesitant now to plan any multi night or even overnights above 10K.