Invalid URL on preview-link

[vortex852456]

Just open a site with some comments (eg. https://pr0gramm.com/top/3448120)

Then execute this script in the console to trigger the error:
window.open($('.fa.fa-level-up.action.preview-link').first()[0].href, '_blank')

For non-developers: Click the right preview-link button with middle mouse key (opens in a new tab on chrome):

Cause of the behaviour: the URL is https://pr0gramm.com/top/!%20-nsfw/3448120#comment33284228 instead of https://pr0gramm.com/top/!%20-nsfw/3448120:comment33284228