When a link is included in a spoiler, clicking it does nothing. You can try it out below:
Blockquotes aren't affected:
Right-clicking the link and choosing something like 'Open link in new tab' works, but is more cumbersome.
It did work in the past, here is a Wayback Machine copy from March this year from a Puzzling.SE question where the accepted answer includes an uploaded image, which is a link in itself.