Password reset warning: Null principal

When testing password reset and going to the nonce page (from email notification), the following warning is logged in midpoint.log

2022-03-01 17:43:49,938 [MODEL] [http-nio-8080-exec-5] WARN (com.evolveum.midpoint.security.enforcer.impl.SecurityEnforcerImpl): Null principal
2022-03-01 17:43:49,941 [MODEL] [http-nio-8080-exec-5] WARN (com.evolveum.midpoint.security.enforcer.impl.SecurityEnforcerImpl): Null principal

As noted by honchar, this happens if the link from email is opened in a different browser than the one with Forgot password button clicked. I commonly use a incognito/private window for this.