Hello,
I have the same problem.
I know it’s not the best solution but if you replace
_n( '%s item', '%s items', $variations_count, 'woocommerce' )
Thanks a lot, I could make variations work back in the admin.
I don’t have any translation plugin, so I wonder what plugin (maybe the theme?) is interfering.
Theme is Negan (last update from them is december 22), and everything is up-to-date.