We are having a problem with an out of the box approval workflow.
5 Server Farm (2 wfe, 2 app,1 db) SharePoint 2010 Enterprise. (upgraded from moss enterprise)
Every time a user approves a document the document shows as last modified by System Account. However the task associated to the workflow it show correctly modified by the user whose approved the document.
What we tried
Double checked the user policies on central admin and all seems to be ok (as recommended)
Tested on other libraries on the site and they all have the same problem.
Tried with various user (site collection admin included) and the problem persist
Deleted workflow and recreated (problem persists)
Deleted Library and recreated (problem persists)