Got the same problem sometimes if many addons are updated after each other (using the Update all button).
The updated addon is removed from the top of the list (after updte was done) but the green "Updating" text is still shown afterwards.
Same/Similar issue here mostly, the program updates the add-on but after it finished the Updating bar (at 100%) and the text above it remain on screen next to the add-on. A restart of Minion solves this as was said in the OP post.
When updating with the 'Update All' button it even happened to me that it "garbled" (don't know how to better describe it) the loading bar and update text a bit after it was finished.