There will be an update to PowerCMS coming out that will upgrade the version of the FCKEditor to version 2.6.5. We do not have a release date for the update at this time, all I can say is that is is planned.
I have tested the behavior of the CKEditor demo site at:
and a similar issue exists, so this appears to be a problem inherent in the FCKEditor. The work around that Neil posted in his reply of selecting all of the cells, then copying and pasting the table still gives the same result of needing to toggle Source code on then off to see the formatting.