Display Name from caller list shortened?

Hello from a noob to Rainbow,

we currently use Rainbow in Connection with our AL system.

Recently I got a call from a User with a long surname (18 characters).
The "missed call" info in Rainbow displayed only 12 characters from the surname and the name.

We already checked the spelling in the AL system, all is well there.
Any ideas?

Best regards,
Norbert Paulsen