In piwik_log_action.name Russian characters are stored with the issues (question marks "??????"). Although, for example, in table piwik_log_action.referer_keyword stored without error...
Judging by the logs errors began in September (occasionally update from SVN)
We do not support direct access to the Piwik database. You must use Piwik's API.
In the case of referer_keyword, Piwik programmatically decodes the referer.
p.s. updating from svn is at your own risk. Make sure you may have this changeset: 
Excuse me, if not described the problem. I'll try again. The error occurs in the derivation of page titles (or rather, at what stage is saved in the database until you can find a method that would show)
In backend looks so: [http://hostingkartinok.com/image/01201110/4274cf70cb2b2299d19b1b106ef758a6.png]
Although the module keywords - works fine:
At least direct where to look. Thanks in advance.
p.s.: I'm using version 5398
hm... problem solved
possibly after removal all
and reboot server