We got some reports from people unable to reboot their nodes after updating to 7.6.1810, and basically to newer shim (v15). It seems to affect only nodes in UEFI mode, but without SecureBoot.
We wrote that in the ReleaseNotes, including a link to the bug report : https://bugs.centos.org/view.php?id=15522
We have now a workaround in that bug report, and also a new interim build (not signed by Microsoft yet) but we need feedback , as the only node on which I could test this myself is my old 2008 iMac computer .. :-(
Once we'll have enough positive (but also negative) feedback about this new build, we'll be able to send to Microsoft for signing and so consider that bug closed. Worth also noticing that if we can have that ready in the updates, we'll be able to spin a monthly iso that will then work on such uefi nodes too.
Kind Regards,