While working on a recent project I noticed some strange issues with a managed metadata column in a list. I had created a custom list and I was populating this list with user profiles in SharePoint. The idea being certain users could view and update user profile information without having to have access to central admin.
To achieve this I had a scheduled task which pulled the information into the list and an event receiver which updated the data back into the user profile when an item was updated. This was all working fine, except I started to notice some of the data in the managed metadata column wasn’t correct. My first thought was the code was inputting incorrect data but I ran through the code and it was all working as expected. Things got stranger still when I noticed that if you were on the list view or viewing an individual record the data was incorrect, however if you were editing an item the data was correct.
Having ruled out the code I then compared the options available in the term store on the site and also when editing a user profile in central admin. It was at this point I noticed these options were slightly different. From previously working with the manage metadata service I knew there was a hidden taxonomy list stored at the root of each site collection, rough URL http://SharePointSite/Lists/TaxonomyHiddenList/AllItems.aspx, so I checked this as well and it contained old values so this lead me to believe it was a synchronization issue.
I hope this helps others as when I had a look around there was nothing I could see on this issue.