In the tagging window, if you click on the top line it will show you the tags that MC sees in the files.
If you mean the icon on the left of the top tagging window line, I have it set to "Show Tags with Values" and manually added the conductor tag, but this is probably not what you mean. If I just click on the top line that has the word "tag" in it, nothing happens. I do not understand the question, am I not showing you what MC reports in the tag window?
Yes Options > General has "Update tags ..." checked. Some of the files where the conductor info is missing are brand new rips anyway. The one shown in the screenshot, however, is not. It is ancient and has been in MC for many years.
PS. I did a quick search and cannot find a single track that shows the conductor in MC tag. I know for a fact that all these tracks do have the MP3Tag conductor field filled.