Flickering between two different videos after export

Yes one of the first things I tried. However the export did work. Strangely it appears the text on the project was causing the issue, as when I removed that it worked fine...

Tried clearing media cache?

Instead of using nested sequences: export them to a intermediate codec and use that in the timeline.

Here are some screenshots to hopefully make what is happening clearer.

Thank you for your time.

As requested:

• Issue - I am having a problem exporting a project. On several parts of the video I have two smaller screens showing two different footages. When I am viewing these in the timeline they occasionally flicker between each other, showing the wrong video in the wrong place, but not to a huge degree. However, I just exported the video and when I view the exported video it shows the two videos constantly flickering between each other.
• Adobe Premiere Pro version number: 25.0.0 (Build 61)
• Operating system - Windows 11 Pro
• System Info: CPU, GPU, RAM, HD:

  • CPU: Intel(R) Core(TM) i9-14900K 3.20 GHz

  • GPU (Intel-based Macs and PCs): NVIDIA Geforce RTX 4080 Super

  • GPU driver (PC): Driver version 32.0.15.6094

  • RAM - 96.0 GB (95.8 GB usable)

  • Hard Drive: Samsung 990 Pro SSD on the motherboard

• Video format: Pro Res RAW HQ, 59.94fps (with S&Q turned on on the Sony FX6 to 120fps).
• Workflow details: Tell us any specific info about the project or sequence. For example, is it a multicam sequence?
  • The project uses 4k Pro Res RAW HQ.
  • The specific video I am having issue with has a number of nested sequences, as well as various other basic edits (Text, Images, After Effect Mogrt, VR glow effect native to Premiere).
  • I use the Phantom LUT IceBlue Fx6_65x, with the footage being adjusted to Slog3Cine after import.
• Steps to reproduce - (Very important!) In a numbered list, the exact steps are needed to reproduce the problem. 
  
  • The issue appears when:
    • I displayed one, two or three nested sequences on the main video with a static background.
    • The playback is more or less okay, although very occasionally, if there is more than one of the nested sequences on the screen at a time, one of the videos will flicker (it can be two if there are three videos), showing footage from one of the other nested sequences when it does.
    • I tried to export a portion of the video to check the flickering did not happen on the final product. I exported using the following settings: Preset: Match Source Adaptive High Bitrate (Frame size: Custom 3872x2168. Frame rate: 59.94, Field order: Progressive, Aspect Square pixels (1.0)). Format: H.264. Renderer: Mercury Playback Engine GPU Acceleration (CUDA).
    • When the video had exported the areas that contained the nested sequences constantly flicker, with each video seemingly being displayed in each area for a frame or two.
      • If relevent:
        • When one of the areas display the other video, that video will have the attributes (such as the frame positioning and zoom) of that area, rather than the attributes of the original video. 
• Expected result - What should have happened after the last step?
  • The exported video should only show the nested sequences in the areas specified when creating it.
• Actual result -  What did happen after the previous step? 
  • When the video had exported the areas that contained the nested sequences constantly flicker, with each video seemingly being displayed in each area for a frame or two.