Looks like a security update to me.
Slurm clusters use something called munge for authentication. It could be that the cluster admins have disabled ssh access.
TO check I would write a quick jobscript which produces that nodefile
Then write a bach loop which runs trhoug the list and does
ssh $host date
Or just run a two job interactive Slurm job and try to ssh between the compute nodes
I should say I am basing my response on those first 4 lines, but it is something you should be able to check quickly