WP 4.5 Multisite SSL certificate problem: self signed certificate


I’ve got a multisite setup with Trellis and have just updated WordPress to v4.5. Trellis is configured to use a self-assigned certificate and when I go to Upgrade Network in Network Admin after updating to 4.5, I get this error:

Warning! Problem updating https://subdomain.site.local. Your server may not be able to connect to sites running on it. Error message: SSL certificate problem: self signed certificate

It doesn’t appear that anything has been upgraded because if I go back to Upgrade Network, I’m still given the option to upgrade.

Is there a way to temporarily disable to self assigned cert so that I can run the upgrade? Is it even necessary? I haven’t run in to any obvious issues with the site after updating the WP version.