@topperharly
I´ve found the issue during an deep dive into the config.xml
The SSL Certs are declared in the CertManager/ and ACME List,
but aren´t stored and aren´t part of the Config Backup. So, after recreating the missing three via ACME , i was able to select them in the GUI.
Strange Behavior... but now fixed.
sometimes it´s worth to look under the hood ;)