Edit:
HpLVd may be seed-borne (on the shell) of hops, but overall, HpLVd transmission by seed (at least for hops) is close to insignificant. I haven’t found research specific to the seed-borne transmission for cannabis seeds, but it can be transmitted through seed embryos. Considering HpLVd is transmittable mechanically (scissors, etc.), it’s not impossible that it can be transmitted on the seed coat depending on cultural practices.
Viruses and Viroids Infecting Hop: Significance, Epidemiology, and Management
https://darkheartnursery.com/dark-heart-lab-confirms-hplvd-transmission-through-seed/
Dark Heart’s plant pathology and research team recently announced the finding that the Hop Latent Viroid (HpLVd) seems to be transmissible through seed from infected stock. Leaf tissue from sprouted seedlings were tested and confirmed the presence of the Hop Latent Viroid.
“This important discovery furthers our understanding of how HpLVd is spread. Up until now, we had an idea that the viroid could be transmitted through seed but it had not yet been confirmed.” says Dr. Jeremy Warren, Director of Plant Health at Dark Heart.
While initial results suggest that transmission rate through seed appears low, further research is underway to determine what the actual rate is. Growers should remain vigilant and assume that unless their seeds are coming from a plant that is confirmed to be clean, their seeds may be infected with the viroid.