Since it only has L and N this is an interesting question as there can be no mains leakage unless you touch it.
A device like this probably has a very cheap SMPS in it which is not compliant with the required EMC standards, and the conducted noise could be causing the RCD to detect a fault.
But this does seem to stretch believability, as you would have thought an RCD would need to deal with a lot more EMC before a shitty ~1 watt SMPS would cause a hassle.
Could there be a fault with the socket instead? Perhaps inserting the device into the socket is allowing a conductive path to form, like some kind of conductive gunk stuck in the socket. Or perhaps you have a swapped neutral somewhere, which means that the neutral current is bypassing the RCD, causing an imbalance and trip.