The reason you still practice it cut up is because in your mind you learnt it like that, cut up.
if you look at traditional forms say siu lim tao you build a few moves on it every lesson or every week or whenever and you learn those moves and build up with a few new moves but in your head all of these moves flow because they are short moves one tan sau one pak sau one huen sao , repeated on the other side.
whereas in taiji when you learn a move its a series of moves that lasts maybe 30 seconds so you see it as one move and the transition between that one move and the next is obvious , whereas because the transition between huen sau and tan sao in siu lim tao isnt obvious, because the pause is equal length.
The easiest way is to focus on the parts where the changeover is and just do the isolated moves one after the other as if its a new mini move, for example in 24 form you start with lifting water thats one move and then the left hand goes underneath left leg pulls in and you start a new move which in fact is a series of moves which lasts 30 seconds , isolate the switch over point and practise it repeateadly as if to make a new ""Joining"" part of the form and you will notice the form has no more mental breaks in it.
it is not the physical force which inspires the fear that makes men sick of
soul so much as that which comes from the eyes, some subtle emanation from the personality as a gas that takes the strength from men's limbs.