Forgot to mention: the same error displays on another wordpress install, same PHP version, on both WP version 5.2.7 and 5.5.1. That site is not https like the site from the issue, so that can’t be the culprit either.
Ah wait, I see that the shortcode works in extra’s areas and in the footer. Now I just have to redesign footer or second extras area to 100% width of the viewport.
