Ah, the never ending battle between YouTube and adblock users. If you lost the round-count then you are not alone. This time, users report that Google is hiding comments and video descriptions on YouTube, if a content blocker is used.
One such report comes from Reddit. The user writes that YouTube is not showing descriptions and comments anymore, if an adblocker is turned on.
It would be a new strategy, as Google focused on disabling video streaming entirely for users with content blockers in the past.
While many users might not miss the comments that much, it is another story for the video description, as it may include vital information or links. If you, for example, watch a cooking video, you may find the recipe in the description.
Tests on my own systems using different browsers returned no such blocking. It seems likely that Google is once again testing the waters or rolling out the change over time.
Some users affected by the change noted that reloading the webpage restored access to the description and the comment section. It is probably only a matter of time before filter lists will be updated to reflect the changes.
For now, it is recommended to refresh the page. If that does not work, I suggest using a different browser and / or content blocker. If all of that fails, try playing videos on third-party sites such as Bing Video.
I ran tests with Brave and uBlock Origin in several browsers, and did not run into any of the described issues.

They are still at it.
I had to install a secondary tool for my primary tool to use to be able to continue downloading yt videos. I’m not downloading often, just occasional help stuff, “where’s the temp sensor on a 06 car” type stuff and I’m not going to sit through ads. It was pretty simple, Ari (ChatGPT) walked me right through it.
Speaking of ChatGTP and ads, they said it wouldn’t affect replies, that’s BS but… as someone who thinks unsolicited advertising should be a felony offense, it’s actually not too bad.
I had my first ad experience on ChatGPT (free), it was something I was actually asking about and not some random popup. It didn’t popup at all until I asked about a specific product and then the ads were actually helpful. I even opened several in my browser, to check for instore availability, and eventually added one of the products to the shopping list.
Google could learn from OpenAI. Throw targeted ads at me when I ask and I’ll click, shove them in my face when I don’t ask and I won’t even visit your site.
The user in the Reddit post mentions that they are using AdGuard, so probably an issue with a filter.
I’m using uBlock Origin with Firefox and I don’t have the issues described.