Oh, it's worse than that. The rules behind complex type upgrading lead to even more bizarre results.

There's also a confusion between "subtype" and "recognizable subtype" (that is, something for which SUBTYPEP returns true as a second value). Subtype relations between SATISFIES types aren't even computable.

All this could have been worked through if the standardization process had continued, but commercial lisps ran out of steam to support the rather heavyweight standard making process.