This post on Meta Stack Exchange (found by Mark Kirby) discusses this type of event.
You flagged one post as a duplicate of another - it was actually a question re-posted by the OP.
Before the question you flagged for closure got closed, the target you suggested in your flag was closed as a duplicate of the question that you flagged.
Community♦ cleared your flag (that is, handled it, or deactivated it so that it had no further effects) and marked it "EventInvalidated" (in the flag history, which is not shown publicly). Your flag would have sent the post to the Close Votes queue, but due to the target being closed as a dupe of the suggested dupe, the review also shows as Invalidated in the post timeline.
This meta stack exchange post also explains that some flags are invalidated like this, because there is no reasonable way for them to be resolved. Invalidated flags do not count against the flagger in any way.
These flags used, apparently, to show up in your flag history as "eventinvalidated", but, it seems, now show up as "removed during a deletion", which in this case is very misleading as nothing was actually deleted (this would show up in the timelines of the posts). The wrongness of this message, and the fact that your flag count ends up not adding up correctly seems to be a bug (although I am not sure this linked post actually adequately covers the latter, which was only mentioned in this comment on the post, subsequently moved to chat).
Sorry for the weirdness. Perhaps your flag will turn up in the count eventually.