NGUI UIInput issue with some Android devices (Virtual keyboard is OK, but no letters appears on textfield)

Hello,

The NGUI UIInput works on iOs devices and on all Android devices except those ones : - Samsung galaxy S6 - Wiko ridge fab 4g - Samsung galaxy tab pro - Samsung galaxy tab 4 - Asus zenfone 2 - Samsung galaxy S6 edge

On those devices, the virtual keyboard appears but then, a press on a letter doesn't add it in UIInput... Im using Unity 4.6.8. Have you ever experienced any similar issue ?