Unable to save environment shell variable containing equal sign in value

[WilliBarankin]

Good day! I'm asking for your help how to fix the issue: I'm creating a new powershell session and want to add a new environment variable in Shell->Process->Environment Variables, but unable to do it. As I've found, the = sign in the variable value is the root cause. I do not see any failures or what else, but such variable is not finally saved.
Windterm 2.6.1