I had a similar experience with a couple of people on my team. They kept
trying to "@" a person named Kimberly, whose name always popped up when
we typed "@kim" - however, that wasn't working that day. We discovered
that typing "kimb" worked, and at least the name showed up and we could
tag them. But we also discovered that typing "kimbe" did not work, so it
was extremely bizarre. So maybe try to slowly type in the person's name,
one letter at a time. We were never able to find out from WF what ...