That's normal dream behaviour; I'm pretty sure there isn't a specific name for it. Sometimes stuff like what you've described happens when I'm lucid, sometimes when I'm not; I never actually become lucid from these occurrences, though. Also, more often than not, only small details of things change - the font of graffiti on a wall can change when I look away and look back, for instance. It rarely happens with DCs for me. Sometimes I summon them and they don't look quite right (their face is off, or something), so I look away and then back at them again; if I visualize hard enough they will look better, more normal. But that's more dream control than anything else.

Maybe the fact that things are switching on someone while they're lucid just means they aren't visualizing or taking memory of their surroundings enough? In that case, it might just take practice and then things will stop changing.