I hope you're well.
The latest update to Ultimate Branding brings an enhancement regarding the background images. Unfortunately, the update has disabled the existing login screen images that have been set on sites in my multisite network. I'm not sure whether this is a multisite specific issue or whether the same thing's happening in stand alone installs, as well. Irrespective of that, I'd be grateful if you could look into this.
I've found that if I go into the Login screen settings page for a site, the background image still shows as being current and, if I re-save the existing settings it does resolve the issue. However, it would be preferable not to have to do this for every site in my network and, moving forward, if this isn't fixed, I assume it's likely to happen, again, with future updates, which, isn't ideal either.