This is a transient bug (as per bug 1792948, rebooting the system appears to let it work). I think this would put in pretty clearly as not a grub bug, but rather some issue with firmware/ kernel, or even multipath-tools. Reassigning to multipath-tools; but I'm setting it to Incomplete: either we'll get a new report that it failed again, or this bug can expire.
I have been unable to reproduce this issue in testing at all.
This is a transient bug (as per bug 1792948, rebooting the system appears to let it work). I think this would put in pretty clearly as not a grub bug, but rather some issue with firmware/ kernel, or even multipath-tools. Reassigning to multipath-tools; but I'm setting it to Incomplete: either we'll get a new report that it failed again, or this bug can expire.
I have been unable to reproduce this issue in testing at all.