You may be becoming lucid during a dreamlet (which is the very beginning of a dream). If so, you may want to sit back (figuratively speaking) and just observe the dream before doing anything at all. This may give the scene time to stabilize.

Difficult to say after only four (though this is a great accomplishment--keep it up!). Just keep practicing. The problem may resolve on its own.

I would also recommend some form of stability meditation (shamatha).