This is essentially the same bug as reported in 15 points for answer being accepted not synced until next upvote.
As Jarrod explains in his answer there:
Stack Exchange (the source of those accounts snapshots) is informed of all reputation events through a Redis list, which it processes as those events occur.
...
Any discrepancies are usually fixed very quickly, because a new reputation event carries the user's current rep score - in your case, since no events happened for two weeks, the error persisted
In your case, the "user removed" event was not added to that Redis list, hence the network reputation was not updated. After a "real" reputation event occured (upvote) it was added to the list, and it was all updated as expected.