It's still going on. Watch the VidStatsX numbers every day. Every day during a one hour period, many, many youtubers are losing large amounts of subscribers. Small channels are losing small numbers, and larger channels losing larger numbers, but there does not seem to be any kind of reason for it.... except the more new subscribers you get, the more subscribers YT seems to unsubscribe. Every youtube I know of says it has to be a glitch. YouTube says there's no problem but also won't explain what's happening.