Hi @Moses37043195x77i,
I appreciate you letting us know about this weird issue. The screen movie was helpful.
To troubleshoot, I would examine your workflow. Understanding the system requirements is critical. I would also check the media. If it comes from a consumer device (mobile phone, drone, etc.), consider transcoding the footage to ProRes LT before you begin your session.
To solve this problem, we need more information about your system and media. See, How do I write a bug report? Once
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