Second line in use indicator

Asterisk ver. 2.11, phones are cisco 7941g and 7945. The 7941g’s line 2 is for the 7945 phone. When the 7945 phone is in use then the line 2 button on the 7941g will light up so she knows her boss is on the phone. Recently the light stays lit up. I have factory reset both phones and removed the second line and added it back and the light still stays on.