You'll need to lean back a little bit on the way down by pressing the hips a bit forward.
You're likely allowing your wrists to bend back and elbows to drop behind the bar on the way down and if you don't fix them before the next rep the hips will stay further out. The body has this whacky tendency to want to keep everything in balance.
Post a video according to the guidelines in the sticky and we'll take a look.