Video and Audio Choppy On Initial Playback - despite proxies?

Hi guys, I'm having an issue with Playback where the initial seconds are laggy and choppy and frames are dropped to the point of being impossible to understand. 
I feel this is not performance related as it's a tiny video file.

This only happens for the first 1-2 seconds of playback and it is repeatable every time the playhead is played.  The thing is I feel I've tried all the normal troubleshooting steps and now I'm out of ideas.

Usually, this system has no issues with performance but like this, I am unable to edit. 

Does anyone have any suggestions on what to try next?

Footage DNxHD 720p SQ 8-bit 1280 x 720 25fps

System Samsung Surfacebook 2 - 12th gen Intel i7 16GB RAM SSD

OS Win 11 Latest build

Versions of PP I've tried  24.1.0 & 23.6.2

Graphics - Intel Iris Xe Graphics

I've tried:

• updating the Graphics drivers,
• different versions of Premiere Pro.
• proxies
• Clearing media Cache
• New Project
• trashing preferences
• (no plugins installed)
• Software only and OpenCL 

None of this helped with the issue.

Please let me know if you have any ideas. Thank you.