Connections of Defi Du Seuil remain baffled by his run in the Irish Champion Hurdle at Leopardstown last Saturday.
Last year's leading juvenile hurdler is undergoing tests in a bid to solve the mystery but as yet no reason has been found to explain his lacklustre effort behind Supasundae.
That was his first run since he disappointed on his seasonal reappearance in the Coral Hurdle at Ascot in November when he was found not to be 100 per cent.
"We're still conducting some more tests to see how he is but he seems to be fine," said trainer Philip Hobbs.
"It is still a mystery at this stage. We can't make any plans until we see how we get on over the next few days."
Frank Berry, racing manager to owner JP McManus, added: "Nothing has shown up since.
"He didn't run great. He's having a few tests done and we might know more next week."