Problem with greek characters and Bar Chart

[geo782]

Hi, I have added a chart in my sql report, with data in greek. Greek Title in Chart is displayed ok, legend is ok but axis are displayed as

Κλειστό

and not like "Κλείσιμο...". I have found problem in file chart_report.twig, line 33

"{{ value.getValue()|replace({'\\':'\\\\','"':'\\"' })|raw }}"

I have changed |raw with |json_encode but i get simular wrong values.

What can i do to get the correct output;

George