Forticlient for Linux can only connect to ONE MFA-enabled firewall

I'm running Forticlient 7.0.0.0018 on Ubuntu 20.04. 

I've configured it to connect to my company's Fortigate 100F using SAML, and it works well. I was surprised to see that it appeared to cache both username and password as I only needed to enter those first time I connected. It doesn't even prompt me for a one-time SMS code. The Windows version requires me to enter both username and password plus SMS code every time I connect. Not top security but I must confess it's quite convenient when working from home. 

Now one of my customers has enabled SAML on their 100F as well. When I try to connect to their firewall, Forticlient still tries to connect using my company credentials, even though I specified what username to use when I configured the new client VPN. 

I renamed the ~/.config/FortiClient/Cookies file and that made it possible to enter all credentials and connect to the client's firewall -- but now Forticlient tries to use those credentials for my company's VPN as well!

Everything works well in the Windows client, so what can I do to make the Linux client work the same way?