Re: RP - Volumes not visible in GUI but seen in RP CLI
This can be a size-related matter if we're talking about replica volumes. If not, then I would try to restart the site control RPA (SSH to the cluster management IP using user admin (or boxmgmt in earlier versions) and navigate to  Shutdown / Reboot operations), just as a workaround.
If that doesn't help, I would recommend raising an SR w/ support.
Hope that helps,
Product Engineer - RecoverPoint and RecoverPoint for VMs
Idan Kentor Sr. Principal Engineer - RecoverPoint and RecoverPoint for VMs