voa_version and temp_column_a

when upgrading to 8 we ran into a few issues, one of which was a permissions problem when editing content (this wasnt initially there, but appeared after a while, a week or so), the first error I was seeing was:

Cannot insert the value NULL into column 'temp_column_a', table 'XXXXX.dbo.sf_permissions'; column does not allow nulls.

and the next was:

 Cannot insert the value NULL into column 'voa_version', table 'XXXXX.dbo.sf_permissions_inheritance_map'; column does not allow nulls.

I removed these columns as they seemed to be left over from an otherwise successful upgrade and everything worked fine, then about 2 weeks later both columns reappeared, I deleted them and everything worked and then today the voa_version column reappeared....

What is creating these columns and why????