Here are the relevant parts of my ganesha.conf related to the two EXPORTs with same Path.
This is the state before, when booting guests was consistently failing.
NFS_CORE_PARAM {
   mount_path_pseudo = true;
}
EXPORT {
   Export_Id = 10101;
   Path = /pool/vm-images;
   Pseudo = /export/ss1/vm-images;
   #Tag = ss1;
   SecType = sys;
   Access_Type = none;
   Squash = All_Squash;
   FSAL {
     Name = PROXY_V3;
     Srv_Addr=10.168.168.1;
   }
   CLIENT {
     Clients = @vh;
     Access_Type = RW;
     Squash = No_Root_Squash;
   }
}
EXPORT {
   Export_Id = 10102;
   Path = /pool/vm-images;
   Pseudo = /export/ss2/vm-images;
   #Tag = ss2;
   SecType = sys;
   Access_Type = none;
   Squash = All_Squash;
   FSAL {
     Name = PROXY_V3;
     Srv_Addr=10.168.168.2;
   }
   CLIENT {
     Clients = @vh;
     Access_Type = RW;
     Squash = No_Root_Squash;
   }
}
This is the the state after I changed the second EXPORT Path to differ from the first.
NFS_CORE_PARAM {
   mount_path_pseudo = true;
}
EXPORT {
   Export_Id = 10101;
   Path = /pool/vm-images;
   Pseudo = /export/ss1/vm-images;
   #Tag = ss1;
   SecType = sys;
   Access_Type = none;
   Squash = All_Squash;
   FSAL {
     Name = PROXY_V3;
     Srv_Addr=10.168.168.1;
   }
   CLIENT {
     Clients = @vh;
     Access_Type = RW;
     Squash = No_Root_Squash;
   }
}
EXPORT {
   Export_Id = 10102;
   Path = /pool/vm-images2;
   Pseudo = /export/ss2/vm-images;
   #Tag = ss2;
   SecType = sys;
   Access_Type = none;
   Squash = All_Squash;
   FSAL {
     Name = PROXY_V3;
     Srv_Addr=10.168.168.2;
   }
   CLIENT {
     Clients = @vh;
     Access_Type = RW;
     Squash = No_Root_Squash;
   }
}