Any reason why Soviet 5 kopeks are set to 4.6 gram

Any reason why Soviet 5 kopeks are set to 4.6 gram? That's 0.4 grams off.

standard circulation 5 kopek weight was not changed between 1926 and 1991 (Source - https://en.numista.com/catalogue/catalogue.php?id=404). You could count stash of 1, 2, 3 and 5 kopeks by weight.

It is a mistake in the catalog. The Soviet lower denominations after 1926 had a weight that coincided with their face value (1 g, 2 g, 3 g, 5 g).

Mine 1973