Audio Only Playing on One Side in 9:16 Format

Hello everyone, I have a small issue. Here's the situation: when I want to edit a video in Premiere in the 9:16 format, it only plays my audio file on either the left or right side, even though I recorded it in stereo. No matter what settings I adjust—whether applying the "Left to Right" effect or vice versa, or changing something within the audio channels—nothing seems to work. If I play my audio through the audio channels section, it plays back in stereo just fine. However, outside of that, it doesn't. It's quite odd because when I edit videos in 16:9 format, everything plays back in stereo without any issues. What can I do to resolve this problem? Unfortunately, neither YouTube nor Google were able to provide a solution.