Using plugged headphones is causing issues

Brand spanking new MacBook Pro 16in, 2021. Apple M1 Max

I've been using plugged Sony headphones to do video editing. I use Premiere. Premiere is not the sharpest tool in the shed, so when I plug in the headphones, I have to go in Preferences and tell it that headphones are plugged in and that it should use them for sound output (duh!). This has been the case since my previous Macbook Pro.

But in this new 16", when I take the headphones out, and I go play something from my computer, it plays for a few seconds and then goes silent. It happened last week while recording a Zoom call with the headphones out, when I played back the video, I heard a few seconds, then it went silent. I thought zoom wasn't recording audio and it ruined my morning because I thought I didn't capture the sound. But it did record it. I realized it when I plugged in the headphones back in. I could hear people talking in the call, but could not hear the video playback. Very odd.

What seems to be happening is that the Macbook doesn't realize headphones have been unplugged, so it stays in headphone mode. If I go into Syst Pref > Sound > MacBook Pro Speakers then I can hear sound again.

I should add that I have 2 new 27 Apple Studio Displays hooked up to this Mac. They are not hooked up directly because Apple was lame/cheap so you can't daisy chain the monitors, so it's all hooked up via a Thunderbolt hub I had to buy separately.

Anyone else running into this? Definitely seems like a glitch of some kind. In previous Macs, when you had the headphones in, sound came out of those. you took them out, it came out of the computer's speakers. Pretty darn simple.