SIP alias with only one 0

Hi.

I would like to know if it’s a bug or there’s some reason to not be able to put a 0 (zero) into the field SIP Alias.
Every number works fine excepted the zero.
00 works fine.

Have you got any idea about this issue?

I talk about Freepbx 2.6, 2.7, and why not 2.8

Regards