The British showjumper fell unwell and was unable to compete in his classes as planned.
Robert had high blood pressure but told H&H he is now feeling in good health and is back in training as usual.
“I’m fine, I’ve started riding again now,” he said on 21 October.
“I just had a high blood pressure for some reason, but it seems to be ok now.”
Robert, whose father is John Whitaker, was due to jump in the Addington Manor talent seekers and Connolly’s Red Mills senior newcomers championship on 7 October.
John stood in for his son in the talent seekers riding Hold On Tight II, finishing fourth.
Phillip Miller rode Noble Warrior for Robert in the newcomers championship. The pair had four faults in the first round.
Robert has had a successful year to date.
In May, the 32-year-old helped take the British team to victory in the Nations Cup in Italy.
“It was absolutely fantastic. My job is made very easy by having a fantastic squad of riders, who were fabulous today,” said team performance manager Di Lampard at the time.
On 28 June he won the Equerry Horse Feeds CSI4* at Bolesworth International riding USA Today.
“I had quite a good draw today and it worked well for me. There weren’t many jumping clears in the jump off and it did take a bit of jumping,” he told H&H at the show.
“Today suited him as there were lots of tight turns there in the jump off and he’s so careful.”