Reproduction steps:
1. Open the attached project “BooleanToolCrash”
2. Open the Boolean Tool (Tools > ProBuilder > Experimental > Boolean (CSG) Tool)
3. In the Boolean window attach “Cube” GameObject to the left side of the window and “Cube (1)” to the right side of the window
4. Click on the “Operation” drop-down menu and change it to Subtraction
5. Slightly change the scale or positioning of both cubes
6. In the Boolean window click on Apply button

Expected result: The subtraction object is created
Actual result: Silent crash

Reproducible with: 5.0.3 (2021.3.29f1), 5.1.0 (2021.3.29f1, 2022.3.5f1, 2023.1.5f1, 2023.2.0b1)

Reproducible on: Win10, Win11

Notes:
It might take a single time (if lucky) or up to 50 times to reproduce the issue.
It is possible that this only reproduces when changes are unsaved.