Nintendo of Europe blocks access to 18-rated content on the Wii U eShop at certain times of day, system messages suggest.
Users are unable to access trailers for 18-rated Wii U games or buy 18-related content.
The issue first came to light after a NeoGAF user experienced the issue and contacted Nintendo of Italy's customer support.
"Dear customer," a Nintendo representative replied, "we would like to let you know that Nintendo has always aimed to offer gameplay experiences suited to all age groups, observing carefully all the relevant regulations regarding content access that are present in the various European countries.
"We have thus decided to restrict the access to content which is unsuitable to minors (PEGI) to the 11pm - 3am time window."
Eurogamer has just tested this and it appears to be true. We were unable to access Assassin's Creed 3 information or buy ZombiU digitally.
"You cannot view this content," a message reads. "The times during which this content can be viewed have been restricted."
There messages appear for user accounts on which no parental controls have been set.
Eurogamer has contacted Nintendo for more information and will update when we hear back.