It would appear so. 12 volts cannot be both low voltage and extra low voltage. It is either one or the other.
Only in your mind, because
you have decided that the terms are intended to be mutually exclusive, rather than ELV being a sub-category of LV.
If one defines an "adult" as being someone aged 18 (or 16) or above, that does not preclude there being a subgroup of adults called "the elderly" (say, over 65). You presumably would not suggest that one cannot be both "an adult" and "elderly", such that one can only be 'one or the other', would you?
It is not unusual for bureaucrats to be incorrect.
True, but just as legislation which contains errors remains "the law" unless/until parliament amends it, so do definitions produced by 'bureaucrats' charged with producing those definitions remain officially 'correct' (even if they contain errors) unless/until the bureaucrats amend their published definitions.
In my opinion, the only saving grace is that virtually none of the general public are ever exposed to this confusion (only in quibbling in forums like this), since otherwise I think it would be very dangerous. Whether you like it or not, I am sure that the vast majority of the general public believe that "Low Voltage" electrical things are, for example, things that they can safely allow their children to play with (even if they have screwdrivers in hand!).