Proposed resolution:

Change [facet.ctype.char.members], paragraph 4, to read

Effects: The second form, for all *p in the range [low, high), assigns into vec[p-low] the value table()[(unsigned char)*p].

The description of the vector form of ctype<char>::is can be interpreted to mean something very different from what was intended. Paragraph 4 says

Effects: The second form, for all *p in the range [low, high), assigns vec[p-low] to table()[(unsigned char)*p].

This is intended to copy the value indexed from table()[] into the place identified in vec[].