Lenovo Laptop key X doing the wrong thing

Hello,
Need a little bit of assistance with my Lenovo laptop!
I am using a BTC keyboard connected to my laptop, and the X key don't appear to be functioning properly, each time it is pressed, the minus (-) sign is added to it, sometimes before the x and sometimes after it.

result : X- or -x

This does not happen when typing directly onto Laptop..

Please, it is so annoying whilst typing.. its really driving me crazy!
Any help is greatly appreciated, thanks!