and when Pinkamina and Rainbow Dash struggled cause RD was trying to drag Pinkie to her party.... they got physical as she was literally trying to drag her out by her hooves and Pinkie smashed RD in the head with her flank... on purpose... fighting... yes without the influence of Discord... they do fight physically throwing tree branches in each others face to win a race and otherwise.
Problem twilight?
Doesn't mean they don't make up or no longer be friends and its not like they are ruthless and killing each other.