Lyz is adding strange characters to the first line of .bib file

[farid-zare]

Hi I am using Lyz, and I noticed when I add a new reference to .bib file a strange key is added to the first line like "2_UYD9A23J".
Also when I want to cite the reference in lyx, some entries like year are missing and for author-year formatted citation styles I get errors regarding missing glyphs.
I am also using author-year citation styles in lyx like "Chicago" and "cbe".
I would greatly appreciate it if you can please help me figure this out.