Hmm, I can see what you mean. It surprises me that GSPlan would match, because normally it will only match the start of the word. Maybe it is matching another tag, or perhaps even the standard text. Doesn’t seem right though.
There is no other tags. If it’s match plain text it is also should be bug because I’m searching for tags.
Usually Agenda highlights found text in the note but in this case it doesn’t highlight anything.