My problem is the same as the one described here:
Unfortunately, that post does not offer a working solution.
I've noticed different behavior in the search description when searching for different terms. Sometimes the managed metadata term will show as a string, and sometimes it will show with the ID and GUID in the description, even though both searches are displaying the same document as a hit.
I've also tried mapping the managed metadata column to a crawled property, but I could not locate the crawled properties for some of my managed metadata columns.
Anyone know how to fix this??