Skirmish over Sullust occured hours before the Battle of Endor which the captain of an Imperial II-class Star Destroyer, Supremacy, came into slip space above the planet to be met with a massive rebel fleet, who believed to have been planning a surprise attack on the Death Star II and was attacked by Rose Squadron. The captain reported the fleet but Palpatine disregarded it as he wanted to trap the rebels at Endor.
Rose Squadron later destroyed the Supremacy and any surviving TIE fighters, including TIE/INs which Ruby went after the death of Weiss Jenkins.
Almost every trace of imperial signals were destroyed, even escape pods that were found.