Probably bad deinterlacing somewhere along the way. For too long, half-rate deinterlacing (60i > 30p) has been common. That's starting to change with 60p suppor

Probably bad deinterlacing somewhere along the way. For too long, half-rate deinterlacing (60i > 30p) has been common. That's starting to change with 60p support on major distribution platforms, but in the piracy scene half-rate deinterlacing is still common for many types of content.