I have reached out via chat on Arnott's website and verified that these shocks have a limited lifetime warranty just like the rest of their products.
The language doesn't say anything about magnetic shocks but the agent said it applied there as well. In case they try to use the specific language below to get out of a warranty I sent to chat transcript to my email.
"Arnott LLC® offers a Limited Lifetime Warranty for United States and Canada on Arnott branded Air Springs, Air Struts, Compressors, Coil Spring Conversion Kits and Arnott branded Adjustable Motorcycle Suspension Kits. Orders for Arnott branded products outside of the United States and Canada (i.e., the European Union, Mexico, and the rest of the world) come with a Limited Two-Year Warranty. Arnott offers a 30-Day Money Back Guarantee and a 90-Day Return Policy on unused and uninstalled products. Arnott offers a 30-Day Warranty on parts used in commercial vehicles. Improper use or installation is not a manufacturer's defect and is not covered by the warranty. The Arnott Warranty is non-transferable."