"Bad message" with a new SAN using multipath and iSCSI

I’m configuring a new SAN for a set of Ubuntu 18.04-based servers. Each of nodes can mount the ext4 formatted partition fine.

Being new to both multipath and iSCSI, I’m not sure if what I’m seeing is "normal". I’m having two problems so far.

1. When I create a file with touch, the other nodes do not see it. I’m used to some kind of delay with NFS mounted drives, but basically, the other nodes never seen it (i.e., I’m still waiting and I guess an hour has passed already).

2. More worrying, is that when I list a copied file with ls or du the directory it is in, I get an error "Bad message". I looked around the Internet and it seems the solution is to unmount the drive and then use fsck to check it. That is, data corruption might have occurred. However, on the computer I copied the file with (i.e., computer A), the file is fine. When I ls it with another computer (i.e., computer B), I get this error.

In the management software of the SAN, I don’t see any disk errors.

All of the servers and the SAN are connected to a single switch for a local network. They are physically close to each other — they are in the same rack.

Are these two situations "normal"? If not, any suggestions on what I can do?