In my opinion it is a simple desire of miss nothing.. therefore if a rumor of strange coins come from serious peoples, the
RIC decide to mention it as ''confirmation recquired''. The problem is that 70% of the source are impossible to check online.. some of them are preserved on universities wich ask to be student for key acces.
For this coin it seems that the source is Leningrad Hermitage museum and that the
ZfN coin is with unreadable mark.