Attempting to apply CA VM:Spool 1.8 PTFs published after RSU-1901 (PTF SO10985), VMSES/E reports the PTF(s) cannot be applied because PTF SO10984 is a pre-requisite and is not applied.
PTF SO10984 is installed by installing CA VM:Spool 1.8 RSU-1901 (PTF SO10985) and you do not have RSU-1901 installed.