Why can't i watch videos in landscape while charging my phone?

When watching video in fullscreen in landscape and plugging in my charger, the video changes to portrait. When unplugging my charger it goes back to landscape again. Why is this happening? I'm using a Zenfone 9 (Android 14) and have tested with Firefox (watch YouTube fullscreen) and DRTV app watching in fullscreen with same results. I remember having encountered the same issue on my last phone as well, but haven't tested yet (Sony XZ2C, Android 10). (At first I thought it was an intermitten issue with Youtube or Firefox, but then I figured out it was related to when the phone was charging and reproduceable with other apps.)