"irreproducible" means something that cannot be reproduced or copied exactly the same way. It refers to situations where it is difficult or not possible to recreate or reproduce a specific result or outcome. Full definition
DESPITE the departure of most of its staff last year to form the Annals of Improbable Research, The Journal of Irreproducible Results continues to be published. (newscientist.com)
Your services should be irreproducible by others, and with Insights we aim to do just that. (marketpsychinsights.com)
In addition, they proved irreproducible in mice. (journals.plos.org)