Sandboxed vivaldi browser terminated upon launch

Lately when I run the Vivaldi browser in the sandbox it is terminated upon launch. Monitoring with Sysinternals process explorer shows that it starts up and forks off some subprocesses, then all of them are terminated. Vivaldi works fine outside the sandbox. I have visited every panel of the Advanced settings gadget and examined all the other Tasks on the main gadget that appeared relevant. I cleaned my sandbox and the problem persists even in a clean sandbox.

When I look at the logs I see entries for Vivaldi, with Action “Terminate Process”. This log message is utterly useless, I know that the process is being terminated, I need to know why Comodo is terminating it so I can find and tweak the appropriate setting to keep it from being terminated.

Comodo Internet Security Premium (free version)
Operating System: Windows 10 version 2004, Build 19041.686, Windows Feature Experience Pack 120.2212.551.0
Vivaldi version: 3.4.2115.81