Probably a loose solder joint and the black mark from arcing?
If you have easy access to another cap just replace it otherwise it might still be ok
Thanks for that boots, I did think it may have been arcing.
I don't have another cap here, but I've been looking around for a cap here is Aus but cant seem to find any.
WES components or Element 14 will have the cap your after in Radial or Axial..