Unable to change the "BIND Forwarder Server

We have a BIG-IP Link Controller (v.9.4.4) that has 4 servers configured as BIND Forwarder Servers. We have tried, via GUI, to add new servers to that list, but with no success so far.

 

 

We are allowed to add a new address to the list, but as soon as we click on the "Update" button, the new server disappears from the list. We get the same situation if we try to edit or delete one of the servers.

 

 

Any ideas on how to change this configuration?

 

 

Thanks,

 

evloal