Check Rear Gate Latch Switch
WARNING: This page is about a different car, the 2023 Subaru Ascent. However, it is still accessible from the selected car via links, so may be relevant.
For inspection, refer to "Rear Gate Latch and Actuator Assembly" in "SECURITY AND LOCKS" service information . Ref. to SECURITY AND LOCKS>REAR GATE LATCH AND ACTUATOR ASSEMBLY>INSPECTION>ACTUATOR .