We got an error on package install, and the Salesforce backend team gave us the following error message:
Case-Case Layout: feedLayout is not supported for this layout: Case-Case Layout: feedLayout is not supported for this layout
If I look at the managed layout in the packaging org, there is an option for "Feed-based layout" but it is deactivated for all layouts.
Likewise, if I go to Cases -> Support Settings there is an unchecked option to "Enable Case Feed Actions and Feed Items" which I assume will check the checkboxes above in the picture
In the target org, this option is not there in Support Settings. Chatter is enabled in both the package and target orgs.
We don't even use the Case object in the package so we're not doing anything strange there.
If anyone has a quick fix that would be great, otherwise I guess I'll have to pursue it with SFDC.