As far as I can see your setup appears normal & correct.
The 2 iSCSI shared LUNs are picked up on all nodes (Pikachuxxxxxx...)
The LVMs of the LUNs on the other hand (LUNPROXMOX01 & 02) can only be accessed by one node at a time.
The reason for this is that iSCSI LVM is a RAW shared storage so it is different from other types of shared storage, since it can only be accessed by one HOST/NODE at a time. There is no FS on it that is cluster-aware that actively maintains the coordination.
PVE will manage/activate the volume (LVM) on its own. So if you migrate/move a VM from one node that uses that volume to another node, the volume will then be activated on the target node & deactivated on the source node.
In short: The PVE backend itself implements proper cluster-wide locking.
In your case, it is interesting that the first LVM called LUNPROXMOX01 shows as active on all nodes, I'm guessing this is because it hasn't yet been actively accessed to by any node, as opposed to the second LVM called LUNPROXMOX02 which probably has already been accessed by your RAICHU node. This probably has to do with the storage types you have chosen in PVE for that LVM. Maybe you added a rootdir type to LUNPROXMOX02 as opposed to LUNPROXMOX01 which you did not. IDK, but its probably something like that. Maybe a reboot will change the situation.
LVM iSCSI sharing is often misunderstood by many. Search these forums.
Do note that LVM storage does not support snapshots.
See also
docs.
Please note: I don't use iSCSI - but this is what I've learned in my time using PVE.