Might also be a kind of desynch, as the top50 is handled separately from everything else.
Could be that he had a highscore registered and reset the account (deck is water starter, or very close to that).
Might also be that there's been some confusion on whatever is used to link highscore with game account (say, someone using the same email for two different accounts).
The other case (-375 score fire mark) is Levgre. Haven't seen him post anything about it though.