Phantom Flex4K files read differently across different software, but Premiere reads it the worst. Resolve and Silverstack both interpret timecode start NOT as the trigger point, but as trigger point timecode MINUS number of frames to get the correct TC.

If Premiere could play nicer with .cine files, then timecode marks selected from files that are transcodes made from Silverstack Lab or Resolve would align perfectly with the TC displayed in Premiere.

If you see the attached screenshot, you'll notice a difference of 500 frames (00:00:20.20) between Premiere-ingested cine files (despite being offloaded with different TC settings in Silverstack) and the transcodes off files brought in with GMT for TC.