First: Look in the right rear foot area, and find the light in the wall behind the passenger's heels. Pull the entire lamp from the wall to expose the fuses behind. Pull the yellow 20-Amp fuse near the inner end of the row, then reinsert it. This resets the computer that controls the PSE (Pneumatic Service Equipment). Now try the trunk lid, and see if the soft-close operates, and/or the handle pops back in.
If so, keep an eye on it for the next few days. If it soon stops operating correctly, this usually indicates a leak in the actuator. Such a leak can sometimes be repaired, sometimes requires a new actuator, sometimes it's something else.