Why does it show I have 1200 refund

you'll need to show more detail. 

Have you answered all the questions that TT asked?  Did you enter how much you have already received in stimulus (it is at the very end of the interview process).  Maybe just a coincidence, but $1200 is also the amount of stimulus per tax payer. if you didn't say you already received $1200, TT is going to put $1200 on Line 30 of Form 1040

Did you complete the stimulus section yet ???   Did you get the $1200 stimulus check  this year already? 

The question about the amount you got in the advance stimulus payment doesn’t happen until the END of the interview.  By then the program has already calculated the credit and has included the amount in the refund meter you see at the top of the screen.   UNTIL you get to that screen where you can indicate how much you actually got in the ADVANCE payment the program cannot know what the correct amount really is.  So once you enter in that amount the program adjusts the credit accordingly depending on how much you already got and the refund meter will change appropriately.