How to reproduce:
1. Open the attached “CrashRepro_IN-108503“ project

2. Change "Script changes while player" Editor setting to "Stop playing and recompile"
3. Enter Play Mode
4. Open the “MyMonoBehaviourScript“ Script
5. Edit the Script and Save changes
6. Select the Unity window by clicking on it

Reproducible with: 6000.0.50f1, 6000.0.56f1, 6000.1.5f1, 6000.1.16f1
Not reproducible with: 6000.0.49f1, 6000.1.4f1, 6000.2.1f1, 6000.3.0a5

Reproducible on: macOS 15.6 Sequoia (Intel)
Not reproducible on: No other environment tested

Notes:
- The issue does not reproduce if, instead of clicking the Unity window, Alt-Tab is used or the window is selected by selecting the Unity window via the Task Bar
- Reproducible with Rider, VS Code, and Visual Studio
- Has a chance not to reproduce the first time

IMPORTANT:

The Editor setting must be changed; the bug doesn't repro if left on the default "Recompile and continue playing".

First few lines of the stack trace:
#0 0x007ff81d94a5e3 in -[NSApplication endModalSession:]
#1 0x00000107aca8bc in -[ProgressbarController hideWindow]
#2 0x00000107acb6a7 in -[ProgressbarNotificationHandler handleClearNotification:]
#3 0x007ff81abff68c in CFNOTIFICATIONCENTER_IS_CALLING_OUT_TO_AN_OBSERVER
#4 0x007ff81ac9caa2 in ___CFXRegistrationPost_block_invoke
#5 0x007ff81ac9ca20 in _CFXRegistrationPost