Sometimes, when talking to a vendor who has a secondary menu/dialogue to turn in a quest, pick up items/rewards, or decrypt engrams before accessing their primary menu--especially vendors in the Tower--the side panel folds out, but the camera does not transition and the vendor's nameplate does not appear. Additionally, the secondary menu/dialogue cannot be exited: attempting to dismiss it simply brings it back. The only way to leave the vendor is to fast travel to a landing zone or another destination/activity.