Normally not, but: to make the MITM work, your PC is pre-configured to trust the company's certificate authority as a trusted root. This is not a per-connection

Normally not, but: to make the MITM work, your PC is pre-configured to trust the company's certificate authority as a trusted root. This is not a per-connection setting, it's a global setting in your browser(s) & OS. So, IF they have a technical way to intercept your traffic even if not connected to the VPN, this will keep working. Of course, in some other cases, a client proxy is configured instead of/in addition to a VPN, in which case obviously all your traffic will be sent to this proxy before reaching the internet.