I’ve been on reddit spreading the good word of Lemmy and Kbin, and occasionally the text of one of my comments will be replaced with [Removed by Reddit]

Any idea what could be provoking this? It seems to happen way more often on the big subreddits. It seems automated to me, but sometimes deleting my comment and reposting a copy seems to bypass whatever is doing the deleting? But only sometimes. Idk.