I had this same problem when upgrading to Beta 4. It seems the HDs I have in the dataTale are not being mounted and are not seen in DISKUTIL. All other devices I have connected through the dock are working just fine. In Catalina the dataTale through the TB3 dock worked perfectly with Time Machine and it always has. I would like to avoid upgrading the dataTale as this is used only for Time Machine backups and nothing else; it has proven to be a very reliable device over the years. I bought this particular dock through Macsales specifically for it's support of FW800. I haven't tried calling Macsales or have not yet opened a issue with Apple concerning this failure. I thought I'd try posting here before pursing this through the normal support channels to see if anyone else is experiencing this issue.
thanks in advance for your help
Dan
thanks in advance for your help
Dan