Jenkins does not show styles in HTML reports though they are allowed in CSP

[Nick N]

Hello, guys!

I publish an HTML report generated by my tests through Jenkins HTML Publisher, but the report does not show any css styles. There is an error in the browser's console:

Refused to apply inline style because it violates the following Content Security Policy directive: "style-src 'self'". Either the 'unsafe-inline' keyword, a hash ('sha256-THOk1r6rC4+HM3k9+2D9L3LsMds3+2crJ1U6Db9rsEk='), or a nonce ('nonce-...') is required to enable inline execution.

I tried to change the policy through Jenkins.xml both to style-src 'usafe-inline' as well as leave the parameter empty at all. The changes are applied and shown on the System Properties page: screenshot but the console still shows the error and styles are not shown in the report.

I tried to google, but found nothing helpful. I asked on SO in Russian and English, but no one seems to know. Where should I look to figure out what is my mistake?