I used exactly the same shortcut, and have the same issue.
I had version: 135.0.5973.66
Updated to version: 135.0.5973.92 (didn't fix it)
OS: Windows 11 (64-bit)
My other shortcuts work properly, such as ctrl + shift + T for Telegram.
I even tried changing them (ctrl + shift + T for WhatsApp and ctrl + shift + W for Telegram), but still WhatsApp doesn't open on key press, and Telegram opens and closes normally, so the problem is not the keys, it is WhatsApp.
Hope any of this helps for solving the problem.