Cookie Firefox issues SameSite

I got this on Firefox:
Some cookies are misusing the recommended “SameSite“ attribute:
Cookie “machete_accepted_cookies” will be soon rejected because it has the “SameSite” attribute set to “None” or an invalid value, without the “secure” attribute. To know more about the “SameSite“ attribute, read https://developer.mozilla.org/docs/Web/HTTP/Headers/Set-Cookie/SameSite

Not sure how important is this.