It would seem that the minting of coins of the Second Republic has already been completely researched and described. However, it turns out that something new can still be discovered. An uncatalogued until 2021 hybrid, where the stamps used for the minting of the DEAD BANNER with a date offset - the DOUBLE DATE (as on the DEAD BANNER
https://onebid.pl/pl/auction/604/lot/498/rrr-5-zlotych-1930-gleboki-sztandar-niekatalogowany ) were assembled for the minting of the reverse, while a stamp typical for the minting of circulation coins was used for the reverse. An extremely rare coin, last listed with us on WDA-MiM 25/405
https://wda.onebid.pl/pl/monety-rrr-5-zlotych-1930-hybryda-awers-gleboki-sztandar/2049324, where a piece in MS62 condition reached a price of 9758zl. A COIN FOR THE BEST COLLECTIONS.