Uki: manual enroll keys succeeded only after a few retries

[nianyush]

Kairos version 3.0.11

I built the ISO with auto enroll set to false. After I reset the device into setup mode, i am able to the boot menu to enroll the keys. However, when i clicked on it, it instantly exited and return to boot menu again(seems like rebooted). And I cannot find any errors on the screen. However, after a few attempts(around 5 or 6) on choosing the enrollment boot entry, it was finally able to enter into the screen which would enroll the keys. After that, installation is also successful. I also checked that all the keys enrolled after that looks correct. Any idea where i can start to debug?