It appears the error is in testing this condition at all:

((objPtr)->typePtr == NULL) && ((objPtr)->bytes == NULL))

A valid Tcl_Obj must follow the stork model. It must be
standing on at least one leg.  The condition above is
testing

  "If this stork is standing on 0 legs..."

which has to always report false.

Removing that seems to be the better solution, unless
we can find some reason it was placed there that makes
sense.