Default input language on servers required to be English Australian, can’t remove English (United States).
Try this on the Citrix servers and remove the English (United states) from the control panel area regional settings etc.
I had the same problem – Microsoft article 322042 should do the trick. Basically all you have to do is add in a:
DWORD value IgnoreRemoteKeyboardLayout = 1 under HKEY_LOCAL_MACHINESYSTEMCurrentControlSetControlKeyboard Layout
Also works with any workstation.