(Rewritten somewhat for CX2.)
In CX1 block templates were skipped unless they were whitelisted and parameter-mapped. This made sense for infoboxes that have a lot of hard-to-adapt parameters. But navboxes and other templates that don't have parameters can usually be auto-adapted, and shouldn't be skipped.
In CX2 this still appears to be the case for some templates. Navboxes for example, are still not auto-adapted even when a corresponding template is available, even though they are usually simple and have no parameters.