[TYPO3-Solr] solr not returning results as expected for tt_news categories

[Jernej Zorec]

Hello,

I would need some explanation why solr doesn't give me expected results.
Clean TYPO3 introduction package with solr extension and enabled tt_news 
indexing. Everything is getting indexed as expected, and when I try get 
tt_news records from solr with this request:
http://localhost:8080/solr/introduction/select/?q=type%3Att_news
everything looks fine.

You can look at the whole response here:
http://pastebin.com/X0gy6tw1

The important fields are the keywords and category which look fine to me:

<arr name="category_stringM">
   <str>Breaking</str>
</arr>

<arr name="keywords">
   <str>buhu</str>
   <str>lolek</str>
</arr>

The typoscript solr configuration is the default one from the file:
solr/static/examples/indexqueue-ttnews/setup.txt


And now when I search for one of the keywords with:
http://localhost:8080/solr/introduction/select/?q=buhu
I get expected result. The whole document and also if I do the search 
over the TYPO3 search in frontend I get the result.

But, when I try to search for the title of the category with:
http://localhost:8080/solr/introduction/select/?q=Breaking
I don't get any results.
Shouldn't solr return the same result as with the first search?
The category is correctly stored in category_stringM field.

I have the same problem in one of my extbase extensions, where I 
configured the SOLR_RELATION for everything and the same problem occurs. 
That's why I'm testing this on a clean intro package and with tt_news to 
figure out how results should get returned.

Regards,
Jernej