Steps to reproduce:

1. Create or open a URP 3D Project
2. Import the attached Font file
3. Select it in the Project Browser and click the kebab menu icon at the top right corner of the Inspector Window
4. Select "Create Font Asset"
5. In the Font Asset Creator Window click the "Generate Font Atlas" button

Actual results: Editor crashes on tlsf_free, looks like a memory crash

Expected results: No crash occurs

Reproducible with versions: 6000.0.71f1, 6000.3.12f1, 6000.4.1f1, 6000.5.0b1, 6000.6.0a1

Reproducible on (OS): Windows 11
Not reproducible on (OS): macOS 26.3.1

First lines of stack trace:

0x00007FFA34A04469 (Unity) tlsf_free
0x00007FFA34A34A8B (Unity) DynamicHeapAllocator::Deallocate
0x00007FFA34A33867 (Unity) DelayedPointerDeletionManager::CleanupPendingMainThreadPointersInternal
0x00007FFA34A31BC3 (Unity) DualThreadAllocator<DynamicHeapAllocator>::Allocate

 Notes:

• Issue reproduces with any Font file
• If crash doesn't first occur, restart Project and do the reproductions steps again, sometimes just waiting after creating the Atlas will crash with a memory stack
• Issue reproduces around half the time when you click the Generate Font Atlas button