MissingReferenceException during image import to Tile Palette when in Tile Palette Edit mode

Steps to reproduce:

1. Create and open a new 2D UPR project
2. Create a Triangle Sprite png in the Project tab (Create -> 2D Sprite -> Triangle)
3. Create a Tilemap grid in the Hierarchy
4. Open it in the Tile Palette window 
5. Create a new Tile Palette
6. Enable the Tile Palette Edit mode
7. Drag the Triangle png into the canvas
8. Create an asset from the png
9. Observe the Console and Tile Palette

Actual results: "MissingReferenceException: The object of type 'UnityEngine.Tilemaps.Tilemap' has been destroyed but you are still trying to access it." is thrown, the Asset is not instantiated into the Tile Palette

Expected results: Nothing is thrown, the Asset is not instantiated in the Tile Palette

Reproducible with versions: 6000.0.0f1, 6000.0.76f1, 60000.3.16f1, 6000.4.9f1, 6000.5.0b10, 6000.6.0a5

Tested on (OS): Windows 11 Pro (25H2)

Notes:

• Sometimes happens only on the second import of the same png
• jpg files are also affected