problem exporting a chart with 2 lines - lines not generated

I have a problem when exporting a chart with 2 grouped by ids. This is how my chart looks like when it is generated:

And this is how it looks like in pdf when generated:

I have noticed that this is also not working on other charts which use 2 grouped by values. All other charts that doesnt include some more advanced queries and grouping are working fine. Is this a bug? Or can anyone suggest me a better solution? I need to have charts in this way

ScreenShot024.jpg

ScreenShot023.png

any reply would be appreciated (helpful :D)

Hello,

Issue reported to our bugs team.

regards,
Bernhard Bernsmann