[CentOS] kernel update doesn't update grub.conf

Just updated another machine to 5.3, everything fine, but grub.conf wasn't 
updated to the 128 kernel. It got a new modified date and the kernel is 
there, but the content wasn't changed. /etc/sysconfig/kernel contains the 
correct UPDATEDEFAULT=yes
No errors in logs or during the update. No problem to boot with this 
kernel once added.
This is the first time I ever see this happen.
Any clues?

Kai

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Kai Schätzl, Berlin, Germany
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