Fedorin’s version: Soviet officials, in order to automate the sale of goods with payment using circulating coins, on the eve of the 1961 reform, ordered vending machines abroad. These machines came with sample coins that imitated USSR coins (of the 1961 reform). The samples were made (minted) abroad as well (possibly a mintage of a few hundred pieces). Later, the automation of selling goods in the USSR for small change did not take off. The machines were not purchased, and the samples for these machines remained unused.
Sample of the State Bank of the USSR 1 Kopeck 1961.