Current SiteAwareTemplateAvailability proves to be too restrictive when working with e.g. jsp (sub-) templates. It used to be possible to combine various templates / renderTypes in one site definition.

Additional details from Tobias:
Allow site definition template availability on templates not using the site renderer.
This is kind of a big change but it would make sense to use the template availability configuration on the site definition also for templates not using the site renderer.

For instance plain text templates or jsp templates.

And for Blossom templates which is a special case in that those templates use the blossom renderer to call into Spring and then render their views using the site renderer. In this scenario SiteAwareTemplateAvailability checks the render type and sees blossom and therefor fallback to the default template availability strategy.