When setting the Program Monitor to "Fit," the preview scaling breaks and glitches during playback. Additionally, there is severe UI lag and stuttering when adjusting sliders in the Lumetri Color panel.

System Specifications:

• Premiere Version: 26.2.0 (Beta)
• OS: Microsoft Windows 11 Pro
• CPU: Intel(R) Core(TM) i7-14700K
• GPU: NVIDIA GeForce RTX 5070 (Secondary: Intel UHD Graphics 770)
• RAM: 32 GB

Issue 1: Program Monitor "Fit" Scaling Glitch When I import a 4K video (or any resolution video) and set the Program Monitor scale to “Fit”, it does not display correctly. As soon as I play the timeline, the preview scaling breaks and glitches.

Steps to Reproduce Issue 1:

1. Import a video into a sequence.
2. Set the Program Monitor zoom level to “Fit”.
3. Play the timeline.
4. Observe the scaling glitch/distortion in the preview monitor.

Issue 2: Lumetri Color Panel UI Lag The Lumetri Color panel sliders experience noticeable lag and stuttering when adjusting parameters by moving the mouse up and down.

Steps to Reproduce Issue 2:

1. Open the Lumetri Color panel.
2. Click and drag to adjust any of the color sliders (e.g., Exposure, Contrast).
3. Observe that the UI stutters and the adjustment does not track smoothly with the mouse.

Expected Behavior: Smooth timeline playback with correct visual scaling when set to "Fit", and a responsive, lag-free UI when adjusting Lumetri Color sliders.