APFS warnings in Disk Utility

Hi,

running a 2012 or so MacBook Pro, with 750Gb SSD with latest High Sierra. I've been getting the following warning in Disk Utility

warning: inode_val:object (oid 0x10040afb2) invalid bsd_flags (0x1081c)

Disk Utility then finishes by saying that the disk seems OK.

I've cloned the disk with Carbon Copy Cloner and erased the drive completely and restored back to the new APFS volume.

Disk utility still shows the exact same warning but only in the second of two snapshots on the newly restored volume.

What does this warning mean (if anything), why does it only appear in the second snapshot and can I ignore it or does it suggest some developing problem, for instance with the SSD?

Any help appreciated

Cheers

Iain