Bug: Instant crash when using mat_reloadallmaterials when a material is flashing

[lunairekitty]

Describe the bug

If you run the convar mat_reloadallmaterials while you have a material flashing via mat_texture_list it will instantly crash the game.

To Reproduce

1. Open a map
2. Make a material flash with mat_texture_list
3. Run the command mat_reloadallmaterials

Issue Map

Not applicable

Expected Behavior

When I use this command it shouldn't instantly crash the game.

Operating System

Windows 11 25H2