It is happening because, each time you are scrolling the tableview, your cells are reused and in that case cell is not nil and the code above the code before the cell==nil
, makes the userInteractionEnabled to NO. That's why, your button is not clickable.
First time those buttons are clickable because they were not allocated, I mean the cell was not allocated and setting any attribute to non-allocated entity makes no effect. Hope you got the point.