Internal error Could not set addresses for U frame

[jmkristian]

When attempting to connect via AGWPE with a very long call sign, Direwolf outputs to the log:

Source Address is too long. "TOOLONG" has more than 6 characters.
Internal error in ax25_u_frame_debug: Could not set addresses for U frame.
INTERNAL ERROR:  lm_data_request NULL packet pointer. Please report this!

So I'm reporting it. A complete log is attached. This is mostly harmless, but it's annoying that it repeats the attempt several times before sending a 'd' disconnect frame to the AGWPE client. A swift rejection would be better.
tooLong.txt

[wb2osz]

AX.25 source, destination, and digipeater addresses are limited to a maximum of 6 uppercase letters and digits, optionally followed by an SSID in the range of 1 to 15.
It's not the most user friendly error message, but the application is trying to send an invalid address.
It's a defect in the client application.