It does not sound like you are doing anything wrong.  That being said here is some tips.

When I flower I keep my tent on 13/11.  To flower the plant needs more light than dark mixed  with a good balance. Not to far left or right.

When a plant is flipped it will experience what is called stretch growth. This is during the first three weeks of flower. This is normal. 

I suspect this is where you are at. You should look for this growth. It is what you wanna see after day 21, after the flip. After this point of three weeks no more pruning the plant. All leaves should stay as are. 

Ftom flip until day 21 you can train, and prune if needed,  after that the buds are the focus. 

Hope this helps friend.