I look for the root of the issue and came to the point that Wizard group should not have any items. All items MUST be moved to region or removed, otherwise this TEMPLATE error will be generated. May be this rule need to be added to JHS developer guide.
Thanks for the info. I was able to reproduce your issue.
Rather than updating the JHS dev guide, we will fix the error, because in previous versions it worked fine to have some or all items in the group itself.