Zero values not showing in line charts

Hi all,

I recently upgraded my Dashboard Design and have one of the latest service packs installed SP06. V6.0.5.0.

I opened up a visual I built in a previous version of Dashboard Design and now the line charts are not displaying 0 values, making my line charts look odd.

I am pasting two images below to illustrate the issue. One for before and for after. I've reduced the number of lines to make it clearer.

Before:

After:

If anybody else has experienced this issue or can suggest a workaround or fix that would be great.

I've tried searching through the threads but couldn't find any other thread with this issue.

Many thanks in advance.