How far was the feeder from your shooting location?
I am listening with earbuds. The first shot sounds like it hit metal. It is did not sound like a carcass hit (but this isn't definitive, of course). It actually sounded like you were shooting a steel target. There is no impact report from the second, third, fourth, or fifth shots. The 6th and 7th had an impact report.
Just a suggestion. You should consider turning off the automatic NUC function. While it is handy, running in the semi-auto mode means you need only press a button to NUC when YOU need to NUC and you don't have to worry about it NUCing in the middle of a shot sequence as happened here when have have hindered you from taking an 8th shot.