I think they're asking if youtube have changed the algorithms because they've suddenly lost 10 subscribers without growing any.
and if that IS what they're asking; then the answer is that youtube are always tweaking their algorithms to try and point content to the people who'll want to watch it. that may impact subscriber GROWTH but it certainly wont cause subscribers to unsubscribe from your channel.
What youtube DO do periodically is run verification checks on accounts to make sure their views and subs are legitimate and not spam or bots. if they identify fake channels or bots they'll remove those because they're against the rules. so my guess is they've identified 10 bots were subbed to your channel and removed them.