Bad NFS exports from older versions makes it difficult to change exports after upgrade

Customer upgraded to TrueNAS 11.3-U2.2 and got the following while trying to add a new system to the NFS exports for a share:

"Another NFS share already exports this dataset for this host"

The IP address they were adding was not the IP address that caused the problem. Instead, there were 3 duplicated addresses in the exports prior to their attempt.

I think there's two issues here:

1) The error message doesn't call out which IP address is duplicated. That's not a problem when the exports list is just a couple items long, but it's hard to spot when there's dozens.

2) I think this checking is helpful, but I think it's more strict than previous versions, such that upgrades with a bad exports list cause unexpected troubles. Perhaps this could be fixed in the database migration? Duplicate entries could be silently discarded then.

Debug attached. (Customer has a plethora of problematic host exports in this debug.)