TheQuartering on YouTube put out a video about an article in PC Gamer, based on a Reddit thread which states that YouTube is implementing features to slow down users that have ad-blockers's PC by using more resources (CPU). Some users have reported overheating as a result, which could lead to permanent damage (it is not clear whether there have been any confirmed reports of damage yet).
Irrespective of where you stand on the issue regarding ad-blockers, purposefully damaging people's equipment is neither a legally or morally supportable solution, and I trust that Norton will treat this as the malware it is, and that they will keep an eye on developments in this regard.
In the meantime everyone should keep an eye open for any unexpected/unusual activity in their CPU utilisation.
sources:
https://www.reddit.com/r/youtube/comments/195octe/youtube_started_slowing_video_buffer_with_adblock/
https://www.pcgamer.com/its-not-just-you-youtube-is-slowing-down-your-pc-if-you-have-adblock-installed-by-making-your-cpu-sweat-likely-as-part-of-its-draconian-war-on-ad-blockers/
https://www.youtube.com/watch?v=KUrRGDt40i8