@lostgen Actually other instances have reported higher load too.
Check the stats at https://mastodon.fediverse.observer/list : mastodon.social has 13 % of total users active in the last month, vs. e.g. 40 % in troet.cafe. So it stands to reason that returning users might create bigger swings in one case than in the other.
However I have no information to doubt Gargron's assessment on the source of today's downtime.