we had a number of site collections with the same guid.
this caused a problem when trying to reduce the number of content databases.
we found that an export and import using PowerShell cmdlet Export-SPWeb to generate a .cmp worked on some site collections.
but on some we found that duplicate webparts where added to the page.It was also discovered that this duplicate web part issue was also present on all standard lists and affects various form views like EditForm.aspx
Is there a fix for the duplicate web part issue. Is this fault due to versioning and duplicate web parts being appended to a page during the import process. If there was a suitable fix for the broken form view .aspx pages then this option is a possibility.
Given that the original .bak files are good, does the possibility exist of MS scripting a GUID update on the site collections to enable moving them into the same content database. If this was feasible then we can bypass the problematic .cmp import process?