then the same LUN was presented simultaneously to the other server
this is the key pt as per my prev qn; how was it 'presented' ie what protocol eg via a SAN, sshfs, nfs ... ?
Which system is the LVM disk(s) actually/primarily attached to? If the 1st system, then check those links to fix the cfgs on the 2nd system.
If the disk(s) are attached to the 2nd system, then you may also have to look at fdisk.