vstam on "Bulk action to add tags stopped working after updating"

Hello!

Just updated to 1.4.5.8 and I can no longer add tags as a bulk action.
I tick the images I want to add tags to, I select 'Add tags' from the 'Bulk actions' drop down list, I select the tag I wish to apply from the dialog and press OK, I press apply, I get the confirmation message('Tags added for selected items')- but when I check, no tags are applied.
I can still add tags on a one to one basis. I can delete images using the bulk action tool.
Any ideas?

Thank you!

Vas