Are you using Developer Mode or made changes in it?
No
Brief description of the issue:
ATC is sometimes missing the first number in my name.
My plane name is 1978 and ATC sometimes call me 978.
It is of course written 978 in the ATC window.
Frequently, the first call to you from any ATC facility will be your full registration number and all subsequent calls are just the last three of your registration.
Regards