Problems with Conten-Type: "application/vnd.hbbtv.xhtml+xml; charset=utf-8"

Dear Piwik team,

we have tracking problems with files that have the content-type “application/vnd.hbbtv.xhtml+xml; charset=utf-8”.
It was defenately working (we are using Piwik for month). We had a database crash a week ago, could this be the problem?

Works (Content-Type: text/html)

Does not work (Content-Type: application/vnd.hbbtv.xhtml+xml; charset=utf-8)

HTML and JS Code is equal.

Any idea what we can do to fix that? Any config stuff?

Thanks in advance,