I noticed the previews in Telegram for post-links do not get the actual post preview.
Actual post link:
Some related SO:
For example, I can randomly /?v=3333 to my link, and can see that Telegram fetches new metadata for the URL, but in case of a specific post, the same is shown, makes me wonder if the issue is on Discourse side?
I’m not sure this is Discourse-specific, I tested the URL above in a) a different Discourse instance and b) an Open Graph tester like opengraph.xyz, and both show the correct excerpt.
Perhaps Telegram is doing something different.. the issue is not happening in Discord as well.
This is what Telegram is looking at:
<link rel="canonical" href="https://meta.discourse.org/t/preparing-for-discourses-upgrade-to-ember-5/287211?page=3" />
Which links to: Preparing for Discourse's upgrade to Ember 5 - #48 by david
This is matching with the content Telegram is fetching as seen in my screenshots 
EDIT - this post from 2022 seems related.