i was unsubscribed from one of my favourite youtube channels by youtube

why does this happen? ever happen to you? i was a bit worried by it as i never did it myself, i never unsubbed from this woman, youtube unsubscribed me from her, i love her channel, she does vintage book uploads, so wondered why it happened and how?

i just posted a comment on her latest video telling her what happened, wishing her a merry xmas and told her i'd subscribed again, i suppose that's the best i can do....but felt annoyed with youtube for unsubscribing me in the fist place.