It depends where your custom overlay comes from.
I’m guessing the orange overlay was copied from the first version of Reboot which would tie in with the thanks and signature text colour problem. If so you will either need to start over or use an editor to compare for differences. If your going to compare then you should be looking for variables that are different / need removing / need adding / need their rule updating.
It would be worth looking at the latest theme update changelog which details the changes you need to make to bring your custom theme up to current version spec.
Usually you shouldn’t need to do that with a child theme, but in this case with Reboot being so new unfortunately these changes were essential.
Is everything else up to date?