Chrome blocks CORS requests to `/advert/*`

After a long time of debugging, I've found the following strange Chrome behavior:

CORS requests to localhost whose URI starts with /advert and contains another slash (yes, it's that specific) get blocked by the client. They work in Edge and Firefox. Changing any letter in the URI so that the prefix is no longer /advert (or remove following slashes) results in the request going through and touching the server. Clearing app data/cache or using private browsing has no effect.

The screenshot illustrates the issue. The status code 0 indicates that the request did not leave the client. Is there a documented reason for this?

enter image description here