core – Cross-Origin Read Blocking (CORB) blocked cross-origin response

I’m experiencing a strange behavior on one of the WordPress sites I maintain (https://www.delscookingtwist.com/) whereby a video won’t play. All that shows up is a black rectangle with the controls (play, pause…). This is true of the video on the home page and not any other video anywhere else in the site (inside posts…)

To be more specific the issue only happens with the owner of the blog, when using Google Chrome Version 86.0.4240.198 (Official Build) (64-bit). This is true both in a normal window, whether logged in to the WordPress backend or not, and in incognito.
On the same Windows PC, the video plays fine in Internet Explorer and in Chrome’s guest mode.
On the same Windows PC and the same Chrome but logged in as me into Chrome (adding a user in Chrome from the Chrome person feature), the website works just fine. I know, it sounds nuts.
On 2 of my work PCs (both Windows 10) using either of Chrome or IE, the website works fine as well.

I eventually found this warning message in Chrome’s Developer Tools’ Console

Cross-Origin Read Blocking (CORB) blocked cross-origin response
https://www.youtube.com/watch?v=gI-Li2QiOik&feature=youtu.be&_=1 with
MIME type text/html. See
https://www.chromestatus.com/feature/5629709824032768 for more
details.

So apparently the video is blocked due to CORB. I did a bit of googling around including on SE where I found several posts about users developing Chrome plugins. This is not the case here.

I’m trying to figure out what the root cause is. Is it due to the plugin being used on the home page in combination with a Chrome extension the owner would have installed in their browser? The blog uses Genesis as a template framework combined with the Brunch Pro theme. I believe the video widget comes from WordPress itself.

Any idea on how I can resolve this?

See also https://stackoverflow.com/questions/51228653/unable-to-load-youtube-video-using-video-tag-where-youtube-url-is-inputted-in

Thanks all and apologies for a really lame question.