How do you stop extra line of time entry being added automatically on Interims time entry?

When you enter an off cycle interim and enter a line of time entry, calculate it then save it, go back in to review/revise it and you notice that the system automatically added another line of pay type 1 regular pay with no hours. Not sure why this is happening or if it's a bug. Tried removing pay on std hours from ee master but no change. EE has no default auto pay type value in ee master. Checked P050002a and Processing Options on P07210I for settings but no luck there. Is there a setting somewhere that controls this automatic