Samsung came into the firing line after owners of its new Galaxy Note 5 smartphone complained their devices could be damaged by a simple mistake with the stylus.

Unlike earlier S Pen iterations, the current stylus is the same width all the way along, which means it can accidentally be inserted into the storage compartment the wrong way around. Android Police reported that issues with incorrectly-inserted S Pens include sticking or broken pen detection.

Bloomberg reported that Samsung had acknowledged that putting force on an incorrectly-inserted stylus to remove it “could damage the S Pen and the device, resulting in malfunctioning”, although it continued that this “doesn’t mean that it’s a defective product”.

The stylus is an important differentiator of Samsung’s Galaxy Note line against a raft of competing large-screen devices from vendors including Apple (iPhone 6 Plus).

Android Police noted that Samsung includes a warning about incorrect storage of S Pen in the user manual, indicating it was aware that potential damage could take place. It said that with earlier devices, it would take substantial force to incorrectly stow the stylus, but with the current incarnation, inserting wrongly has no noticeable difference to correct use.

But Ars Technica pointed out that Samsung does not ship a manual with Galaxy Note 5 – it is only available online.