In Pokémon BDSP, the fixed (invariant) value for the HOME Tracker ID is not set.

[sumo]

① Transfer an Arceus from BDSP → HOME → BDSP to have a HOME Tracker ID assigned to it.
② Using PKHeX, create a new Arceus (with completely different TID/SID, IVs, ball, etc.) and copy-paste the assigned HOME Tracker ID onto it.
③ For some reason, this newly created and edited Pokémon can then be transferred to HOME. ※ When trying to send two or more at the same time, Error Code 10000 occurs, but transferring them one by one works fine.Based on this behavior, I concluded that due to BDSP’s special handling (such as transfer restrictions on Legendary Pokémon), the HOME Tracker ID is not being assigned its proper invariant/fixed value. If you have any additional information on this, I’d appreciate it.

[theSLAYER]

Yes. It is known that some immutable values are incorrectly set to mutable on HOME’s end. Due to the inherent risk from performing such research, and the potential abuse that can arise from this discussion, further research and discussion has been deemed to be not necessary.

cheers.