Link posts from thetyee.ca appear to be previewing the Cloudflare captcha challenge “Attention Required! | Cloudflare” prompt instead of actual content.
What it looks like (two examples - this seems to be a consistent problem for thetyee):
(from https://lemmy.ca/post/39053782)
(from https://lemmy.ca/post/39058782)
What it should look like (a different post):
My guess is that the rich link preview is generated in Lemmy’s backend, and Cloudflare thinks that the IP address of lemmy.ca’s host is full of bots.
No educated guess on the solution, though, but I’d guess that other Lemmy admins have seen sort of thing too.
That’s basically what I do for CBC articles because they don’t generate a preview for some reason. You could plausibly automate this in JS on the client side. Could even be a separate, user control where the user has to click a button for the functionality to trigger. Could be implemented in an alt client too. There are options, they just need work. :D