From 21 October, YouTube automatically pauses five things on a channel where it detects unusual or unauthorised activity: uploading or updating videos and Shorts, switching videos from Private to Unlisted or Public, starting a live stream, creating or adding to playlists, and uploading custom thumbnails. Its security teams review the account, typically within 24 hours.
PPC Land reports that the pause sits on the channel, not on one login, so owners and channel managers are both blocked. If a hijack is confirmed, the limits stay until the owner re-secures the account and contacts support.
PPC Land also notes that two YouTube pages disagree on whether existing videos stay public, so treat that part as unconfirmed.
My read: this protects viewers, and it also means a frozen channel can't show up where people research before they buy. Peak weeks are the worst time to find out.