I tried running it in command line and producing mobi file (to get fuller picture I omitted "--test"). And yes, I do get the same (or a very similar) problem. Only about every third article has a title. Here you can see the file I generated:
https://db.tt/wavF6eN4
Here is a page that ended up without a title:
http://www.lrytas.lt/print.asp?k=new...15991382340219
and this one got a title:
http://www.lrytas.lt/print.asp?k=new...75391380839523
I have no clue why...