How to reproduce:
1. Open the “CTS_WebGL.zip“ project
2. Build and run the “SampleScene“ for WebGL
3. Enter “5“ into the text field in the Player
4. Press the “Start“ Button
5. Wait 5 seconds
6. Observe the text to the left of the “Stop“ Button

Expected result: “Is Cancelled: True“ is displayed
Actual result: “Is Cancelled: False“ is displayed

Reproducible in: 2021.3.45f1, 2022.3.51f1, 6000.0.24f1

Reproduced on: Windows 11 Pro (23H2), macOS 15.0.1 (M1) (by the reporter)
Not reproduced on: No other environment tested

Note: Works correctly in a Windows Player and the Editor