Fortigate 5.6: SSL Interception / certificate issue

[SMabille]

Hi,

Configured with self-signed trusted root CA (same root CA been used since 5.2 without problem)

Strange issue on 5.6 (on 200D) proxy-mode, after a while (few hours) it seems that SSL Interception generated certificate are not valid.

Particularly visible on iOS devices complaining that certificate is not trusted.

Wanted to check if anyone had similar/related issue before opening ticket, as had to revert to 5.4.4 due to the issue.

Thanks