How to reproduce:

1. Open the attached “IN-142433“ project
2. Open “SampleScene”
3. Open Window -> 2D -> Tile Palette
4. Enable overlays (Three-dot menu in the Scene view -> Overlays -> Enable Overlays)
5. In the Tile Palette window, select "Random Brush"
6. In the Random Brush settings, enable Pick Random Tiles
7. In the Tile Palette, select several cells from the palette, ensuring that at least one selected cell is empty
8. In the Tile Palette Brush Pick overlay (the button with the eyedropper and star icon it the Tile Palette window), save the current brush pick
9. Repeat 5-8 steps several times to create multiple saved Tile Palette Brush Picks
10. In the Tile Palette Brush Pick overlay, select one of the saved Random Brush Picks
11. Move the cursor over the Tilemap in the Scene view without painting
12. Observe the Console

Actual result: Console throws “InvalidCastException: Specified cast is not valid” followed by “GUI Error: You are pushing more GUIClips.” than you are popping
Expected result: Hovering over the scene tilemap with a saved Random Brush pick containing empty cells should not produce console errors

Reproducible with: 6000.0.0f1, 6000.0.75f1, 6000.3.16f1, 6000.4.8f1, 6000.5.0b9, 6000.6.0a5

Reproducible on: Windows 11
Not reproducible on: No other environment tested

Note: The issue only reproduces when the saved Random Brush Tile Palette Brush Pick contains empty cells. The issue does not reproduce when the saved brush pick contains only tile cells.