Sonni says she spotted the mark on Ava in April 2017 and that the girl told her, "Daddy bit me," according to papers filed publicly in the Superior Court of California in Los Angeles last week.
"It's OK Mommy, it was an accident. I told him to never do it again," Ava said, according to the docs, as the filing explained, "Later, (Ava) explained that the bite happened when (Jeremy) was being mean and yelling."
However, in separate emails, Jeremy denies allegations the bruise came from him, saying Ava's seat belt "pinched" her. Sonni goes on to challenge her ex, writing, "When… putting some ointment on her owie, Ava told me you bit her there."
"Ha. No. We do a nibble game called Ava burrito. Haha. But not a bite," the star insisted. "Tell her she's spicy. And the game ensues. Haha. Nibble game are fake nibbles."
The "Wind River" actor's rep slammed the claims on Tuesday, calling them, "Categorically not true and another straight-out character assassination made by Ms. Pacheco and her attorney," adding that after Sonni claims the incident took place, she still "never sought a restraining order or never withheld Mr. Renner's 50 per cent custody time."
The battle to strip each other of custody rights took a turn last November, with the actor's ex claiming he talked about killing her before turning a gun on himself while he was high on drink and drugs.
Sonni also had her nanny file a declaration as part of her petition seeking heightened protection in court, accusing Jeremy of firing a gun into the ceiling of their home while Ava was sleeping during the furious rant. Meanwhile, the star maintains Sonni is mentally unstable and is spearheading a smear campaign against him.